Host report keeps the last backup across a restart; Secure Boot meta-package leaves the Proxmox lane

Found in the 2026-10-09 kernel-night read-back:
- demo-felhom: the kernel step restarted the host 4 minutes after the night
  backup; the in-memory backup list was empty after the restart, so the hub
  alarmed "host tier: newest backup is 48h old". The report now adds R-894's
  saved newest success per tier (one shared instance).
- demo-hp: proxmox-secure-boot-support pulled shim-signed-common into the
  ring-0 Proxmox plan; the step was refused R6 and the kernel step skipped.
  It joins HOST_SLOW_RE with shim and GRUB.

Red-proved: TestCollectBackups_SavedSuccessSurvivesARestart,
TestR894_LastKnownBackupsIsWiredIntoTheDaemon,
test_ring0_pending_pve_leaves_the_secure_boot_meta_out.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

.claude/rules/unprompted-work.md

@@ -23,7 +23,8 @@ unconditional: true
 customer data; anything that changes a promise the product makes to a customer; anything that
 reverses a documented design decision (`documentation/architecture/` — a design decision is not a
 defect, R-370); anything on DooPlex or ep0; baking or vouching a golden; promoting a
-catalog version; a new external dependency.
+catalog version; a new external dependency; **a hub image build or hub deploy in a session the operator does not
+attend** (operator ruling 2026-10-07, `09` §3 decision 162).
 
 ## 2. When you may decide instead of ask (operator grant, 2026-09-14)
 

CHANGELOG.md

@@ -1,4 +1,157 @@
-## Unreleased (2026-10-06 night, later) — after a restart the agent remembers the last backup per tier (R-894); three more SMART counters on the wire (R-330)
+## Unreleased (2026-10-08) — no OS leg after a household press; the after-boot kernel report carries the real ring (R-899); no „wrong code" when older packages were not checked (R-304); the last backup survives a restart in the host report; the Secure Boot meta-package leaves the Proxmox lane
+
+**Delivery: the agent binary AND the config bundle** — the wrapper `felhom-os-apply` changed (2026-10-09).
+
+- **The hub's backup evidence survives a restart (2026-10-09, found in the kernel-night read-back).** The host report's
+  `backups` list came only from memory, which is empty after an agent restart. On demo-felhom the night backup landed
+  02:40 UTC and the kernel step restarted the host at 02:44 — no report fell in between, two nights running — so the hub
+  alarmed „host tier: newest backup is 48h old" at 03:00 after a good backup. The report now adds R-894's saved newest
+  success per tier and guest (`backup-success-state.json`, ONE instance shared with the local API) where memory holds no
+  success at or after it. Only successes are saved, so a failure is never hidden. `hub.KnownBackupReporter`,
+  `BackupSuccessState.KnownBackupSuccesses`; tests `TestCollectBackups_SavedSuccessSurvivesARestart` (red-proved: the
+  restart case reported nothing), `TestBackupSuccessState_KnownBackupSuccessesSurviveAReopen`, and
+  `TestR894_LastKnownBackupsIsWiredIntoTheDaemon` now also asserts the collector gets the same instance (red-proved).
+- **`proxmox-secure-boot-support` is a boot-chain package (2026-10-09).** On demo-hp (Secure Boot on) its upgrade pulled
+  `shim-signed-common`; in the ring-0 Proxmox plan that refused the whole step (R6) and skipped the night's kernel step,
+  after the household had been told „tonight". It joins `HOST_SLOW_RE` with shim and GRUB (they stay out of every lane,
+  as before). `test_ring0_pending_pve_leaves_the_secure_boot_meta_out` (red-proved).
+
+- **R-899 (operator ruling 2026-10-08, option A):** `POST /backup?trigger=manual` (a „Mentés most" press, sent by the
+  controller from its next release) runs no OS leg after it: the leg belongs to the night, after the night's own copy.
+  Before, a press ran the leg at once (in the day; on 2026-10-07 08:51 demo-hp skipped it only by the 20-hour rule). A
+  request without the parameter (an older controller, the scheduled path) behaves as before.
+  `internal/localapi/server.go`; `TestAfterPrimaryBackup` gained two sub-cases (red-proved: ignoring `trigger`, the leg
+  ran once after a press).
+- **R-304 — „wrong code" only when every earlier package was tried.** `POST /escrow/recover-offsite-password` answered
+  400 („the recovery code did not open the sealed bundle") whenever the current package and the TRIED earlier packages
+  refused the code — even when the hub withheld earlier packages (rows with no key material, rows over its serve cap), a
+  served package was malformed, the 6-attempt cap stopped the loop, or the retained list could not be read at all. Now
+  those cases answer **424** with `older_unchecked` (the count, -1 = unknown) and a sentence that does not call the code
+  wrong. `escrow.ErrRetainedUnchecked` / `RetainedUncheckedError`; the retained fetcher's second value is now every
+  withheld package (unopenable + truncated + malformed). Tests `TestR304_*` (real age crypto; red-proved: without the
+  check, four cases returned the wrong-code error) and a 424 row in `TestRecoverOffsitePassword_EachSituationGetsItsOwnStatus`.
+  An older controller maps the unknown 424 to its neutral „we do not know why" sentence.
+- **The „ring 1" label after a boot:** in the first second after a reboot the agent has not fetched the hub's block, and
+  the after-boot kernel reports (`judging`, `good`, `revert`, `fell_back`…) said ring 1 on a ring-0 box (demo-felhom,
+  2026-10-08 night). Now they read the fetched block, else the block the daemon saved on disk before the reboot (R-866),
+  else ring 1 as before. A label only — the hub's approval reads its own ring list. `kernelReportRing`,
+  `TestKernelReportRing_BeforeFirstFetch` (red-proved: ring 1, want 0).
+
+## v0.153.0 — ring 0 stages exactly the told kernel (R-898; `09` §3 decision 176) (2026-10-07)
+
+Released by `scripts/release-agent.sh`: binary sha256 `b204ebe6d65944f43b70dcfa4ae0dfb90da38c92e2ba6a38a1826e488eeb6630`, bundle
+`6db216275eb0dd39188d93481a2045998a69e8cb7838ad908a58d65d9a6a9b57` (tag `v0.153.0` = `2d1e5d0`). Delivered (binary only — the
+bundle files are unchanged from 0.152.0) to demo-hp, demo-felhom, Tester 1 on 2026-10-07 19:03.
+
+**Delivery: the agent binary only** — no root file changed (the wrapper is unchanged; its tests gained two cases).
+
+- `internal/osupdate/kernel.go`: ring 0's night kernel step stages EXACTLY the kernel the household was told about
+  (select `listed`, `KernelSet(kver)` = the series meta-package and the signed image at the kernel's own version) instead
+  of "whatever is pending tonight". Seen 2026-10-07: demo-felhom was told about 7.0.14-20 while its sources offered
+  7.0.14-22 by night — the old code staged `pending-kernel` and the wrapper refused it (R23), losing the night. A told
+  version that is no longer installable is refused by the wrapper before any change (R7) and the hub tells the household
+  again for the newer kernel (hub v0.143.1). Tests `TestKernel_Ring0ToldNightStagesThenReboots` (red-proved against the
+  old select), `TestKernelSet`; wrapper `test_ring0_listed_installs_the_told_kernel_not_the_newest`,
+  `test_ring0_told_kernel_gone_is_refused_before_any_change`.
+
+## v0.152.0 — the kernel lane (R-836; `09` §3 decisions 164, 172; `11` §5.11) (2026-10-07)
+
+Released by `scripts/release-agent.sh`: binary sha256 `95ff42208e36ba49b6e2b09a97e81a6fa11562ecc8042f1ed18d378b8b1f88b1`,
+config bundle sha256 `f0c2cec374b711b3c131c955012b33fd0ad495337d049b7a743c3eef9e85c20b` (tag `v0.152.0` = `d03ab7f`).
+Step bundle `0.152.0-step1` sha256 `0b71d32b054cf3b7ade0234ffcbb0df159901f542cde540adaee411db466f48e` (the 0.151.0 bundle
+with only `felhom-os-apply` replaced; `scripts/build-step-bundle.py`), published as package version `0.152.0-step1`.
+
+**Delivery: agent binary, then the STEP bundle `0.152.0-step1`, then the bundle `0.152.0`** — the bundle ADDS two paths
+(the GRUB generators), and an installed `felhom-os-apply` refuses a path its own table lacks (R16, R-880).
+
+A new kernel boots ONCE; if it crashes the box comes back on the old kernel by itself; it becomes the default only after
+a healthy boot; a booted-but-unhealthy kernel is reverted ONCE by the agent with no person. Built on the spike's
+candidate 2 (`audits/kernel-spike-2026-10-07/`), with option C on the one-shot entry.
+
+- `configs/felhom-grub-oneshot.sh` → `/etc/grub.d/01_felhom_oneshot` (bundle): reads `felhom_next` from a GRUB env block
+  on the ESP (`EFI/felhom/oneshot.env`), clears and saves it BEFORE the menu, and sets the default to that kernel's
+  one-shot entry only when the name is an installed kernel. No vfat ESP → prints nothing.
+- `configs/felhom-grub-oneshot-entries.sh` → `/etc/grub.d/42_felhom_oneshot` (bundle): one entry per installed kernel,
+  id `felhom-oneshot-<ver>`, the normal entry plus `softlockup_panic=1 hardlockup_panic=1 hung_task_panic=1 panic=10`
+  (option C). Sorted after `10_linux`: never entry 0, never the default.
+- `configs/felhom-os-apply`: layer `kernel` (lane slow; an appliance; authority = a signed `os_kernel_step` or the
+  root-owned ring-0 mark). Modes: `apply` STAGES (select `pending-kernel` or a signed `listed` set; `expect_kver` = the
+  kernel the household was told about): pins the GRUB default to the RUNNING kernel in
+  `/etc/default/grub.d/zz-felhom-kernel-default.cfg` and proves it from grub.cfg, installs, proves the default did not
+  move and the one-shot entry exists, writes the flag; never reboots. `kernel-reboot` (a staged step only),
+  `kernel-boot` (judging | fell_back | self_reverted | revert_failed), `kernel-good` (the new kernel becomes the
+  default, proved), `kernel-revert` (ONE per step; refused when the default is not the old kernel), `kernel-cancel`,
+  `kernel-status`. New refusals: R20 (the box cannot do a one-shot: not UEFI, no vfat ESP, a separate /boot, GRUB
+  without fat/loadenv, the generators missing, a hand pin), R21 (the crash guard tripped or an unclean boot in its
+  window), R22 (the phase does not allow the mode; never two steps within 20 h), R23 (not exactly one newer kernel, or
+  not the one signed / told). State `/var/lib/felhom-kernel/state.json`. Facts carry `kernel_lane`; the next-boot
+  kernel reads the flag and the grub.cfg default. Tests: `KernelLane` (27), red-proof
+  `felhom.eu/documentation/audits/kernel-lane-2026-10-07/A/redproof.txt`.
+- `configs/felhom-crash-guard` unchanged; `KernelStepCannotLeaveTheBoxOff` (3 tests) pins that a step's planned reboot,
+  one crash and one self-revert add ONE unclean boot (a panic before userspace adds none), so the box cannot stay off.
+- `internal/osupdate/kernel.go`: the night leg ends with the kernel step — after a healthy host step (and a healthy
+  Proxmox step when one ran), trigger `night` only, on a night the hub's `os_update.kernel` block marks `tonight` (the
+  household was mailed the day before — no mail, no step). Ring 0 stages + reboots; ring 1 reboots only a kernel a
+  signed `os_kernel_step` staged (`KernelStepExecutor`: stage only, under the heavy-op gate). The hub hears `staged`
+  BEFORE the reboot. At every start `KernelAfterBoot`: on the new kernel it JUDGES the boot — `KernelVerdict` = the
+  host health rule (`11` §8.2) AND the box reached the hub (the `judging` report itself) — for 20 minutes (measured:
+  everything healthy 68 s after the reboot on demo-felhom, 272 s on demo-hp; under the hub's 45-minute `host_stale` (`alerting.stale_threshold`)).
+  Healthy → `kernel-good`, outcome `applied`; not healthy → outcome `health_failed`, then ONE `kernel-revert`.
+  Tests: `TestKernel*` (13); red-proofs in the same file.
+- `internal/hub`: `WireOSUpdate.Kernel` {kver, tonight, notified_at}. `internal/reconcile`: `os_kernel_step` is
+  destructive-class. `cmd/felhom-opsign`: the op is listed.
+
+## v0.151.0 — the agent can no longer hand the guest any image; the Proxmox package lane; the other-key archives reported; the DR directive retired (R-861, R-812 A, R-366, R-105; `09` §3 163, 165, 168, 169) (2026-10-07)
+
+Released by `scripts/release-agent.sh`: binary sha256 `0464354f2cdf452a7c5d2a74d9191fe91415fcfa244154480d26d5b30e10b194`
+config bundle sha256 `bacd1d175a9392bc1755341d01a106abbd72aba48ab575e7a32dd819d8f5da4c` (tag `v0.151.0` = `dd7cdc0`).
+**Deliver the binary FIRST, then the bundle:** the bundle's sudoers removes the `tee` grant the 0.150.0 binary still uses.
+No path added (26 → 26), so no step bundle.
+
+### Part of v0.151.0 — the agent can no longer hand the guest any image; felhom-op's pct lines are exact (R-861 (a) A1, (b) B2; `09` §3 decision 165)
+
+**Delivery order: agent binary FIRST, then the config bundle.** The new sudoers drops the agent's in-guest `tee`
+grant; an older binary still calls `tee`, so a bundle that lands before the binary would stop managed controller
+updates (and the old binary's capability probe would read `controllerswap-write` degraded). No bundle path is added
+(`felhom-priv-apply` and `/etc/sudoers.d/felhom-op` are already bundle files), so no step bundle.
+
+- `configs/felhom-priv-apply`: new verb `controller-image <vmid>` — reads the ref on stdin (≤ 256 bytes, ASCII, one
+  optional trailing newline), requires `^gitea\.dooplex\.hu/admin/felhom-controller:[0-9]+\.[0-9]+\.[0-9]+$` (the agent's
+  own `controllerImageRe`), then runs `pct exec <vmid> -- tee /etc/felhom-controller-image` AS ROOT; refusal rule `I1`
+  (rc 3), a bad vmid `A1` (rc 2); listed in `--self-check`.
+- `configs/felhom-agent.sudoers` `FELHOM_CONTROLLERSWAP`: `pct ^exec [0-9]+ -- tee /etc/felhom-controller-image$`
+  REMOVED; `/usr/local/sbin/felhom-priv-apply ^controller-image [0-9]+$` added.
+- `internal/localapi`: `GuestExecutor.GuestExecStdin` replaced by `WriteControllerImage`; `GuestBinder.WriteControllerImage`
+  pipes `ref\n` to the verb through the fenced runner; the swap's `writeImage` calls it. Capability `controllerswap-write`
+  now probes the verb.
+- `configs/felhom-op.sudoers` (B2, hygiene): `pct start|stop|unlock [0-9]*` → `pct ^start [0-9]+$` etc. (the glob's `*`
+  matched spaces: `pct stop 9201 --skiplock 1` passed).
+- Tests: `ControllerImage` (5, `configs/test_felhom_priv_apply.py`), `TestSudoersRefusesTheR861Injections` (+3 lines),
+  `TestSudoersAllowsTheControllerImageVerb`, `TestFelhomOpSudoersPctIsExact`, `TestR861_WriteControllerImageUsesTheRootVerb`,
+  `TestControllerSwap_WriteViaRootVerb_NoShell`. Red-proofs: `felhom.eu/documentation/audits/day-2026-10-07/C/`.
+- `README.md`: the controller-swap paragraph described the removed `tee` path — corrected.
+### Part of v0.151.0 — the Proxmox package lane (R-812 option A, `09` §3 decision 163)
+
+**MinAgent impact: none** (a new layer; an older hub ignores the pve report). **The bundle carries the new
+`felhom-os-apply` — deliver it with the binary** (signed `agent_update`, then signed `agent_config_update`).
+
+- `configs/felhom-os-apply`: new layer `pve`, lane `slow` only — the host's Proxmox USERSPACE packages: origin `Proxmox Debian Repository` only (R2), never a kernel / boot / firmware / microcode name (R14, `HOST_SLOW_RE` — the kernel is R-836's lane), no removal (R4), no undo (R5), a new package only from `PVE_NEW_ALLOW` (`proxmox-firewall-data`, measured on demo-felhom; R6 otherwise), an appliance only (R12), authority = a signed `os_pve_step` or the root-owned ring-0 mark (R3). Select `pending-pve` (ring 0): installed Proxmox-origin packages with a pending upgrade. The report carries `pve_manager` (pveversion after the step).
+- `internal/pvegate` (new): the agent's own writes to /etc/pve wait while a pve step runs (pmxcfs restarts); the step waits for writes in flight (bounded, 2 min — then it fails and does not run). Wired at `proxmox.Client.doBody` (every non-GET) and `ExecRunner.RunStdin` (`WritesEtcPVE`: pct config verbs, pvesm, pveum, felhom-pbs-apply create/reconcile).
+- `internal/osupdate`: `LayerPVE`; the night leg runs the pve step in ring 0 after a healthy host step (an appliance; ring 1 never in the night leg); `PVEHealthVerdict` = the host rule + every running container keeps its id + pveversion reads the installed pve-manager; the pve report carries Proxmox userspace only (the hub's candidate set). `PVEStepExecutor` (signed `os_pve_step`, ring 1, under the heavy-op gate and the /etc/pve gate); `reconcile.ClassOSPVEStep` (destructive-class); `felhom-opsign -op os_pve_step` (params by `-params`).
+- Tests: wrapper `PVELane` (17; red first — the `pve-manager` plan was refused R12 on the old code), `pvegate` (5), `TestPVEGate_*` + `TestWritesEtcPVE`, `TestPVE_*`, `TestPVEHealthVerdict`, `TestPVEStepExecutor_*`. Red-proofs: `felhom.eu/documentation/audits/day-2026-10-07/B/`.
+### Part of v0.151.0
+
+- R-366 slice 2 (`09` §3 decision 168): the restore-test pick records, per tier, the archives it skipped as written with another key (count, oldest, newest — no key material) in a `ForeignKeyLedger`; the host report carries it as `foreign_key_archives.tiers` (the stanza absent until a tier was evaluated since start, `tiers: []` when none — no null on the wire, the report contract forbids it). The hub turns a change into one operator line. Tests `TestR366_PickRecordsArchivesWrittenWithAnotherKey`, `TestR366_EvaluatedWithNoneIsAnEmptyList` (red-proved, `felhom.eu/documentation/audits/day-2026-10-07/E/`).
+- R-105 option A (`09` §3 decision 169): the `--selftest=escrow-create -directive <file>` flag and the escrow upload's `directive` field are removed — nothing read the directive; the DR path reads the recipe, tenantsync and the escrow blob. The hub ignores a `directive` from an older agent.
+
+## v0.150.0 — the Docker step proves the engine reports a memory kill; after a restart the agent remembers the last backup per tier; three more SMART counters on the wire (R-528, R-894, R-330; `09` §3 decisions 157, 161) (2026-10-07)
+
+Released by `scripts/release-agent.sh`: binary sha256 `a23d1c9085bc7fd4fc48fe0327f6504aa83e6331510fb4a3d23e042dddb26f9c`
+config bundle sha256 `88456b386d9b1027bd22861cac8c23df004bf9fd9f67644d6595bfca8c94498e` (tag `v0.150.0` = `3a72a48`).
+**The bundle carries the new `felhom-os-apply` (the memory-kill check) — deliver it with the binary:** signed
+`agent_update`, then signed `agent_config_update`. No path added (26 → 26), so no step bundle.
+
+### Part of v0.150.0 (2026-10-06 night, later) — after a restart the agent remembers the last backup per tier (R-894); three more SMART counters on the wire (R-330)
 
 Ships with the memory-kill check below as v0.150.0, AFTER the 2026-10-07 night read-back. Nothing delivered tonight.
 
@@ -9,7 +162,7 @@ Ships with the memory-kill check below as v0.150.0, AFTER the 2026-10-07 night r
 - Tests: `TestBackupDue_R894_*` (restart = a new server and a new state from the same file; fresh / old / none / storage answers / failed backup not saved), `TestBackupSuccessState_*`, `TestR894_LastKnownBackupsIsWiredIntoTheDaemon` (AST). Four red-proofs observed (`felhom.eu/documentation/audits/night-burndown-2026-10-06/s4/`).
 - **R-330 (disk health Phase 2, the wire only):** the SMART summary carries three more SATA raw counters — `reported_uncorrect` (187), `command_timeout` (188, carried as the vendor reports it; some pack several counters), `udma_crc_errors` (199). Pointer + omitempty: an attribute the drive does not report is OMITTED (unknown), never 0. No verdict reads them yet. Tests `TestParseSMART_R330_*` (two red-proofs, `felhom.eu/documentation/audits/night-burndown-2026-10-06/r330/`).
 
-## Unreleased (2026-10-06 night) — the Docker step proves the engine reports a memory kill (`09` §3 decision 157, R-528)
+### Part of v0.150.0 (2026-10-06 night) — the Docker step proves the engine reports a memory kill (`09` §3 decision 157, R-528)
 
 To be released as v0.150.0 with its config bundle AFTER the 2026-10-07 night read-back (the night of 2026-10-06 runs v0.149.0 on purpose).
 
@@ -18,11 +171,11 @@ To be released as v0.150.0 with its config bundle AFTER the 2026-10-07 night rea
 - `configs/test_felhom_os_apply.py`: its `unittest.main()` sat in the middle of the file, so 11 tests (UnsentReport, SaveReportOnDisk, AgentDiesMidPass, CrashLeftTheJournal) never ran — moved to the end; all pass.
 - Tests: the OOMCheck class (pass, OOMKilled=false, no event, unreadable image, removal on an inspect error, not on other layers or in health mode, the events window after the settle wait, mode oom-check alone and its refusals); TestDocker_OOMCheckReachesTheHubUnchanged, TestR868_KeptCopyCarriesTheOOMCheck. 12 red-proofs in `felhom.eu/documentation/audits/readback-2026-10-07/F/`.
 
-## Unreleased (2026-10-06 evening) — the shared rule file (`09` §3 decision 152); no code change
+### Part of v0.150.0 (2026-10-06 evening) — the shared rule file (`09` §3 decision 152); no code change
 
 - `.claude/rules/unprompted-work.md` added, byte-identical to the copies in felhom.eu, felhom-controller, app-catalog-felhom.eu and the workspace root (checked with `diff` against the controller's copy and one md5 across all five). Its copies line names five copies.
 
-## Unreleased (2026-10-06 afternoon) — instruction files kept true (`09` §3 decision 150); no code change
+### Part of v0.150.0 (2026-10-06 afternoon) — instruction files kept true (`09` §3 decision 150); no code change
 
 - `CLAUDE.md` „Gates — ONE entry point": the runner runs every gate in its `GATES` table (five: three shared, `published`, `release-complete`); `--fast` skips `published` (network). It said two gates and „all of them".
 - `CLAUDE.md`: the decoy gate and its audit are named with their `felhom.eu/` prefix (they do not exist in this repo).

CONTEXT.md

@@ -1,5 +1,12 @@
 # CONTEXT — felhom-agent working state
 
+> **2026-10-08 (day) — UNRELEASED on main, ships with tomorrow's release (decision 178).** R-899: `POST /backup?trigger=manual`
+> runs no OS leg (`localapi/server.go`); after-boot kernel reports carry the saved block's ring (`kernelReportRing`). R-304:
+> `escrow.ErrRetainedUnchecked` → HTTP 424 `older_unchecked` when not every earlier package was tried (withheld, caps,
+> malformed, unreadable list). Binary-only delivery; no wrapper or root file changed.
+
+> **2026-10-07 (evening) — v0.152.0, the kernel lane (R-836, decision 172, `11` §5.11).** Wrapper layer `kernel` + two GRUB generators in the bundle (delivered with step bundle `0.152.0-step1` — the bundle adds paths, R-880); `osupdate/kernel.go`: night step on told nights only, after-boot judge (host rule + hub reached, 20 min), ONE self-revert, `os_kernel_step` stages only. Proven on Tester 1 (panic → fell_back, held guest → self_reverted, healthy → 7.0.14-22 default). Open: R-898, R-897; the ring-0 night run.
+
 > **2026-10-04 night — v0.143.0 RELEASED + vouched (R-840, decision 96): the config bundle.** `felhom-os-apply` mode
 > `bundle` (signed `agent_config_update`, verified by the wrapper itself; trust files never bundle paths) +
 > `--install-bundle` (installer 1.31.0); `BUNDLE_FILES` is the one table; `scripts/build-config-bundle.py`;

README.md

@@ -44,13 +44,14 @@ unnoticed until a user hit them. `internal/capability` makes that loud:
   (`HostCapabilityChecker`) alerts the operator on a Critical capability going degraded. Serve-degraded
   — the probe never blocks startup. (Next self-health slice: the controller↔agent channel check.)
 
-**Controller-swap under non-root (v0.45.0).** The agent-owned controller image swap
+**Controller-swap under non-root (v0.45.0; the write since R-861 (a) A1).** The agent-owned controller image swap
-(`internal/localapi/controllerswap.go`) no longer shells out: `writeImage` pipes the image ref on
+(`internal/localapi/controllerswap.go`) no longer shells out. The write goes on **stdin** to the ROOT verb
-**stdin** into an in-guest `tee /etc/felhom-controller-image` (via `GuestExecStdin` →
+`felhom-priv-apply controller-image <vmid>` (`GuestBinder.WriteControllerImage` → `Runner.RunStdin`, the same fenced
-`Runner.RunStdin`, the same fenced `sudo -n` runner) — no `bash -c`, no interpolation. Its 5 narrow
+`sudo -n` runner), which re-checks the ref against our registry + repository + an x.y.z tag and writes
-grants live in the `FELHOM_CONTROLLERSWAP` sudoers alias (all read-only or fixed-target; the `tee`
+`/etc/felhom-controller-image` inside the guest itself; the agent has no in-guest `tee` grant any more (before, a
-target is the FIXED image path, content stdin-fed) and in the capability manifest (Critical), so a
+compromised agent could feed any image — sudo cannot see stdin). Its grants live in the `FELHOM_CONTROLLERSWAP` sudoers
-dropped grant is a build failure + a live degraded signal. No general `pct exec` is granted.
+alias (read-only or fixed-target) and in the capability manifest (Critical), so a dropped grant is a build failure + a
+live degraded signal. No general `pct exec` is granted.
 
 ## The `storage` package — observe + watchdog (slice 5)
 

REPORT.md

@@ -1,14 +1,16 @@
-# REPORT — the second burn-down night (2026-10-06 → 07): R-894 and the R-330 wire half, on main, unreleased
+# REPORT — agent, 2026-10-08 (day): R-899 and R-304 on main, unreleased
 
-Nothing was released or delivered (brief fence). Both changes ship with the memory-kill check as **v0.150.0**, after the
+**No release, no delivery today** (kernel night 8→9; `09` §3 decision 178). Binary-only; ships with tomorrow's release.
-2026-10-07 night read-back. Session report: `felhom.eu/REPORT-night-burndown-2026-10-06.md`; night log
-`felhom.eu/documentation/audits/night-burndown-2026-10-06/NIGHT-LOG.md`.
 
-- **R-894** (`74b5eae`): the newest successful backup per tier is kept on disk (`backup-success-state.json` in the OOB
+| Item | Commit | Tests | Red-proof |
-  state dir) and read by `/backup/due` **only when the tier's storage cannot be read**: fresh → not due, older than the
+|---|---|---|---|
-  cadence → due, none → due with age unknown (as before). A storage that answers stays the ground truth. Tests
+| R-899 — `trigger=manual` (a press) runs no OS leg | `4c69c25` | `TestAfterPrimaryBackup` + 2 sub-cases | ignoring `trigger` → the leg ran once after a press (`[8200]`) |
-  `TestBackupDue_R894_*`, `TestBackupSuccessState_*`, `TestR894_LastKnownBackupsIsWiredIntoTheDaemon`; four red-proofs
+| „ring 1" label in after-boot kernel reports (seen 2026-10-08 night, demo-felhom) | `4c69c25` | `TestKernelReportRing_BeforeFirstFetch` | `Block().Ring` → `ring 1, want 0` |
-  `felhom.eu/documentation/audits/night-burndown-2026-10-06/s4/`. Architecture: `07` §6.1 updated.
+| R-304 — 424 `older_unchecked` instead of „did not open the sealed bundle" when earlier packages were not all tried | `91b9405` | `TestR304_*` (real age crypto), 424 row in `TestRecoverOffsitePassword_EachSituationGetsItsOwnStatus` | check off → four cases returned the wrong-code error |
-- **R-330, wire only** (`adaf86a`): the host report's SMART summary carries 187 `reported_uncorrect`, 188
+
-  `command_timeout`, 199 `udma_crc_errors` (pointers, omitted when unknown). No verdict reads them.
+**Read before the change (read-only, demo-hp):** on 2026-10-07 08:51 the morning press DID reach the OS leg
-- Suite `go test ./...` rc 0; `scripts/agent_gates.py` (full) all OK; CI green on each push (runs 1451, 1467).
+(`osupdate: skipped — already ran tonight`, saved by the 20-hour rule only); `os-update-block.json` on demo-hp holds
+`ring 0` (the fallback the label fix reads).
+
+**Gates:** `go build/vet/test ./...` rc 0; `agent_gates.py --fast` rc 0. **CI:** job 1529 (`4c69c25`) success; job 1530
+(`91b9405`) success.

REUSE.md

@@ -15,7 +15,7 @@
 | `SudoHostOps.run` | internal/storage/hostops.go | `run(ctx, name, args...) error` | allowlisted exec with stderr-wrapped error | Every arg pre-validated via validate.go before this is called |
 | `Prober.Probe` | internal/capability/probe.go | `Probe(ctx) []Status` | live sudo-policy capability check (`sudo -n -l --`) | Needs a DIRECT runner (never the sudo-prefixing one — double-sudo); never executes probed cmds. v0.86.0: config-gated caps (`Capability.GatedBy` + `Prober.GateActive`) report `inactive`/"disabled by configuration" ONLY when healthy — broken plumbing stays degraded; the pbsdr-* gate answers from `pbsdr.Manager.DRConfigured` (marker-backed across restarts) |
 | ~~`stageTemp`~~ (REMOVED v0.146.0, R-861) | — | — | — | Nothing the agent writes is `install`ed where root reads it any more: use `felhom-priv-apply` (below) or ship a fixed file in the bundle |
-| `felhom-priv-apply` (v0.146.0, R-861) | configs/felhom-priv-apply | `felhom-priv-apply unit <name> \| dnsmasq <tmp> <name> \| wg \| sshd-config \| sshd-key` | ANY agent-rendered file a root program reads (systemd unit, dnsmasq drop-in, wg-quick conf, OOB sshd) — fixed source + destination, CONTENT checked against the agent's own renderers | A new renderer needs a verb + a contract test (`internal/privapplytest.Check`) feeding its REAL output; never a new `install` sudoers line |
+| `felhom-priv-apply` (v0.146.0, R-861) | configs/felhom-priv-apply | `felhom-priv-apply unit <name> \| dnsmasq <tmp> <name> \| wg \| sshd-config \| sshd-key \| controller-image <vmid>` (the last reads the ref on stdin, R-861 (a) A1) | ANY agent-rendered file a root program reads (systemd unit, dnsmasq drop-in, wg-quick conf, OOB sshd) — fixed source + destination, CONTENT checked against the agent's own renderers | A new renderer needs a verb + a contract test (`internal/privapplytest.Check`) feeding its REAL output; never a new `install` sudoers line |
 | `privapplytest.Check` | internal/privapplytest/check.go | `Check(t, verb, name, content) string` | the Go↔root-checker contract: a renderer's real output must read `OK` | Skips without python3; one call per rendered shape + one refused control |
 | `BUNDLE_FILES` + `Bundle` (mode `bundle`, `--install-bundle`; mode `agent_update` v0.146.0, R-861) | configs/felhom-os-apply | the ONE table of root-owned paths + the installer of them | ANY new root-owned file the installer writes (sudoers line, wrapper, unit) — add it to the table, never a new installer fetch (R-840) | The builder (`scripts/build-config-bundle.py`) and the installer read the same table; `test_every_root_file_the_installer_writes_is_in_the_bundle` fails on a path the bundle lacks. Trust files (`/etc/felhom/os-trust.json`, `operator-signers`) are NEVER bundle paths (R17) |
 | `osupdate.ConfigUpdateExecutor` | internal/osupdate/bundle.go | signed op `agent_config_update` {agent_version, bundle_sha256} | delivering the bundle to an installed box | a courier only: the root wrapper re-verifies signature, host, nonce and sha itself |
@@ -88,6 +88,8 @@
 
 | Symbol | File | Short signature | Use for | Gotchas |
 |---|---|---|---|---|
+| `pvegate.Write` / `pvegate.Step` | internal/pvegate/pvegate.go | `Write(ctx) (release, waited, err)` / `Step(ctx) (end, err)` | R-812 option A: keep the agent's own /etc/pve writes out of a Proxmox package step (pmxcfs restarts) | Already wired at the two chokepoints — `Client.doBody` (every non-GET) and `ExecRunner.RunStdin` (`WritesEtcPVE`: pct config verbs, pvesm, pveum, felhom-pbs-apply create/reconcile). A new root CLI that writes /etc/pve goes into `WritesEtcPVE`, never its own lock. Never take `Step` around anything but the wrapper call (`Leg.runPVE`) — a `Write` inside a `Step` deadlocks until its context ends. |
+| `osupdate.KernelVerdict` / `Leg.KernelAfterBoot` | internal/osupdate/kernel.go | `KernelVerdict(before, after, tunnel, hubReached) (ok, why)` | R-836: THE one-shot-boot rule — the host health rule (`HostHealthVerdict`) AND the box reached the hub since the boot | The only judge of a new kernel. Never reboot the host from Go: every reboot is the wrapper's (`kernel-reboot`, `kernel-revert`), and only for a staged step. A new kernel-lane state lives in the wrapper's `/var/lib/felhom-kernel/state.json`, never in the agent's own files (the agent can write those). |
 | `Client.WaitTask` | internal/proxmox/task.go | `WaitTask(ctx, upid, opts) (TaskStatus, error)` | asserting EVERY mutating op | POST 200 ≠ success; authz can fail at task exec; `AllowWarnings` opt-in |
 | `Client.Pool` | internal/proxmox/query.go | `Pool(ctx, name) (PoolInfo, error)` | felhom-pool membership (the ownership registry, A1) | Needs `Pool.Audit` at `/pool/<name>` (host-install v1.9.0+); `Pool.Allocate` does NOT satisfy the read; members can be storages (type `storage`, vmid 0) — filter them |
 | `Client` mutate wrappers (`RestoreLXC/Vzdump/DestroyLXC/Snapshot/Rollback/SetConfig/ResizeLXC/Start/Stop`) | internal/proxmox/mutate.go | return `(upid, error)` | all API mutations | Async → always pair with WaitTask; route via gate/queue, not ad-hoc |
@@ -168,7 +170,7 @@
 | `backup.SpecBuilder` / `backup.TierPicker` / `(*BackupRunner).PickSettledRestoreCandidateOn` | internal/backup/schedule.go, runner.go | `func(ctx,archive) RestoreTestSpec`; `func(ctx,target,notAfter) (archive,landed,error)` | The per-run restore-test spec + per-tier **settled** candidate lookup (R-85, widened by R-86) | The spec is built **PER RUN**, never frozen at construction — the pre-R-85 immediately-invoked value made the offsite tier unschedulable AND went stale on any config change. `SourceTier` comes from **the archive**, never the configured target (the v0.100.0 rule). A tier with no archive returns `("", zero, nil)` — **`""` is NOT an error**, or every fresh box looks broken for its first week. **R-86: `notAfter` is the settle cutoff** (zero = no cutoff, which is what keeps `PickRestoreCandidateOn` a one-line call into it), and the picker now skips entries failing `archivePlausiblyComplete` — under per-archive due-ness an incomplete phantom would be picked forever, fail forever, never earn proof, and make the tier due at EVERY evaluation. |
 | `localapi.BackupTier` + `normalizeBackupTiers` / `config.BackupConfig.BackupTiers` | internal/localapi/backup_tiers.go, internal/config/config.go | `normalizeBackupTiers(tiers, legacy, cadence) []BackupTier`; `BackupTiers() ([]BackupTier, []string)` | THE R-82 multi-tier resolution — one runner per tier, primary first | **The untargeted local-API contract is FROZEN**: no `?target=` ⇒ primary tier ⇒ pre-R-82 response BYTES (Target is `omitempty` and stays empty). Never default a missing cadence — reject it and log the warning at ERROR. Never share one retention knob between tiers. Jobs are keyed by (vmid,target). |
 | `localapi.StaleLockController` | internal/localapi/stalelock.go | `*staleLockController` (Client + Runner + pool) | `fakeStaleLock` (Server-level) stalelock_test.go; `fakeStaleLockAPI` (controller-level, tests the A1 pool intersect) stalelock_pool_test.go |
-| `localapi.GuestExecutor` | internal/localapi/controllerswap.go | `*GuestBinder` (pct exec) | `fakeGuestExec` internal/localapi/controllerswap_test.go |
+| `localapi.GuestExecutor` | internal/localapi/controllerswap.go | `*GuestBinder` (pct exec; the image write via `felhom-priv-apply controller-image`) | `fakeGuestExec` internal/localapi/controllerswap_test.go |
 | `guestnet.Runner` / `guestnet.GuestSource` (R-54, v0.92.0) | internal/guestnet/{probe,watchdog}.go | `*proxmox.ExecRunner`; the POOL-VERIFIED `localapi.StaleLockController.Guests` (ListLXC ∩ felhom pool, audit A1) | `scriptedRunner` + `fakeGuests` internal/guestnet/watchdog_test.go. **Never wire a bare `ListLXC` here** — under a broad token that would run dhclient inside a co-tenant's container. Every assertion is an exec COUNT, and the load-bearing ones are the negatives: a static guest, an unprobeable guest, a boot-race guest and an unproven guest list must record **zero** heal calls |
 | `guestnet.Watchdog.SetDampers` / `now` (clock seam) | internal/guestnet/watchdog.go | config `guest_net.*`; `now` defaults to `time.Now` | tests advance a manual clock (the storage-watchdog pattern) and assert the heal ceilings EXACTLY — ≥10 min apart, ≤3/hour, and ≤30 over a scripted 10 hours of permanent failure. A damper with no test is a comment |
 | `hub.GuestNetReporter` (R-54) | internal/hub/collect.go | `*guestnet.Watchdog` (`GuestNetStatus`) | internal/hub/collect_guestnet_test.go asserts the stanza through the PRODUCTION `Collect` path AND that the `guest_net` key is ABSENT from the wire when no reporter is wired — an always-present empty stanza would make "not wired" and "found nothing" the same signal, which is the shape v0.91.0 hid behind |

cmd/felhom-agent/main.go

@@ -135,39 +135,38 @@ func main() {
 		return
 	}
 	var (
-		cfgPath       string
+		cfgPath      string
-		selftest      selftestFlag
+		selftest     selftestFlag
-		vmid          int
+		vmid         int
-		watch         time.Duration
+		watch        time.Duration
-		archive       string
+		archive      string
-		mode          string
+		mode         string
-		hostname      string
+		hostname     string
-		keep          bool
+		keep         bool
-		rootfsGrow    int
+		rootfsGrow   int
-		dataVolGrow   int
+		dataVolGrow  int
-		dataVolMount  string
+		dataVolMount string
-		sysDataGrow   int
+		sysDataGrow  int
-		sysDataMount  string
+		sysDataMount string
-		cores         int
+		cores        int
-		memoryMB      int
+		memoryMB     int
-		pbsStorage    string
+		pbsStorage   string
-		paperkey      bool
+		paperkey     bool
-		offline       bool
+		offline      bool
-		upload        bool
+		upload       bool
-		custID        string
+		custID       string
-		custDomain    string
+		custDomain   string
-		custName      string
+		custName     string
-		custEmail     string
+		custEmail    string
-		hubPassword   string
+		hubPassword  string
-		blobPath      string
+		blobPath     string
-		expectedFP    string
+		expectedFP   string
-		keyDest       string
+		keyDest      string
-		installWGKey  bool
+		installWGKey bool
-		idBundlePath  string
+		idBundlePath string
-		directivePath string
+		swapImage    string
-		swapImage     string
+		outputMode   string
-		outputMode    string
+		showVersion  bool
-		showVersion   bool
 	)
 	flag.StringVar(&cfgPath, "config", envOr("FELHOM_AGENT_CONFIG", "/etc/felhom-agent/agent.json"), "path to the agent config file (JSON)")
 	flag.Var(&selftest, "selftest", "run a self-test and exit: bare/`read` = read-only queries; `task` = reversible mutating exercise (needs -vmid); `hub` = one collect+report; `storage` = observe storage (+ -watch); `backup` = one-shot backup of -vmid; `restore-test` = restore→boot→verify→teardown of -archive (or newest backup); `restore-test-due` = READ-ONLY: print the per-tier due verdict the scheduler would act on, with its cost; `pbs-verify` = trigger a PBS verify + print snapshot records; `bring-up` = restore→reset identity→size→start link-up of -archive into -vmid (needs -mode/-archive/-vmid; optional -cores/-memory cap; tears down unless -keep); `provision` = full slice-8A chain: bring-up provision + mint token + populate bootstrap config mount (needs -archive/-vmid/-customer-id/-hub-password; optional -rootfs-grow/-datavol-grow/-cores/-memory (-sysdata-grow is deprecated: folded into -datavol-grow); keeps the guest)")
@@ -198,7 +197,6 @@ func main() {
 	flag.StringVar(&keyDest, "keydest", "", "for --selftest=escrow-consume: where to install the recovered key (0600)")
 	flag.BoolVar(&installWGKey, "install-wg-key", false, "for --selftest=identity-consume: ALSO install the recovered wg_private_key into wgtunnel's key file (S5 DR; create-only, refuses to overwrite)")
 	flag.StringVar(&idBundlePath, "identity-bundle", "", "for --selftest=escrow-create: a 0600 JSON file {tunnel_token,pbs_token} to ALSO escrow under R (10D)")
-	flag.StringVar(&directivePath, "directive", "", "for --selftest=escrow-create: a JSON file with the non-secret DR directive (pbs repo/ns, expected fingerprint, tunnel id)")
 	flag.StringVar(&custID, "customer-id", "", "for --selftest=provision: the customer id — the hub config-pull target, baked into the guest's bootstrap")
 	flag.StringVar(&hubPassword, "hub-password", "", "for --selftest=provision: the customer's hub RETRIEVAL PASSPHRASE (SECRET) — baked into bootstrap.json so the controller pulls its config (and the customer-scoped hub key) from the hub. The customer must already exist in the hub.")
 	flag.StringVar(&swapImage, "image", "", "for --selftest=controller-swap: the target controller image ref (gitea.dooplex.hu/admin/felhom-controller:<semver>) — must already be pulled in the guest")
@@ -269,7 +267,7 @@ func main() {
 				SysDataGrowGB: sysDataGrow, SysDataMount: sysDataMount, Cores: cores, MemoryMB: memoryMB},
 		}))
 	case "escrow-create":
-		os.Exit(runSelftestEscrowCreate(context.Background(), cfg, logger, pbsStorage, paperkey, offline, upload, idBundlePath, directivePath, outputMode))
+		os.Exit(runSelftestEscrowCreate(context.Background(), cfg, logger, pbsStorage, paperkey, offline, upload, idBundlePath, outputMode))
 	case "escrow-consume":
 		os.Exit(runSelftestEscrowConsume(context.Background(), logger, blobPath, expectedFP, keyDest))
 	case "identity-consume":
@@ -792,6 +790,9 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	pbsTargets := pbsTargetsFromPVE(cfg, px, logger)
 	pbsReporter := pbs.NewLiveSnapshotReporter(pbsTargets, pbsStore, pbs.DefaultLiveSnapshotTimeout, logger)
 	collector := hub.NewCollector(px, newTunnelProber(cfg, px), observer, backupStore, backupStore, pbsReporter, cfg.Hub.HostID, version, logger)
+	// R-366 slice 2: the restore-test's ledger of archives written with another key → the host report.
+	foreignKeys := backup.NewForeignKeyLedger()
+	collector.SetForeignKeyArchiveReporter(foreignKeys)
 	collector.SetBackupTargetResolver(primaryBackupTargetOf(cfg)) // R-109: the recipe names the live target
 	// Privileged-capability self-check (v0.44.0): probe the sudoers grants the non-root agent
 	// depends on. The probe runs `sudo -n -l` LITERALLY (a policy LIST, never executing the
@@ -876,6 +877,13 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	go osLeg.SendUnsentLoop(ctx, 5*time.Minute, func(n int) {
 		logger.Info("osupdate: sent kept report(s)", "count", n)
 	})
+	// R-836 (`09` §3 decision 172): what became of a kernel step across this boot; on a one-shot boot of a new kernel,
+	// judge it (the host health rule + the hub reached) for KernelJudgeWait, then make it the default or revert ONCE.
+	// The wait: measured 2026-10-07 (`audits/kernel-lane-2026-10-07/B/`) — every container healthy 68 s after the
+	// reboot on demo-felhom and 272 s on demo-hp (the hub reached at 63 s / 189 s); 20 minutes leaves room for a slow
+	// network and stays under the hub's 45-minute host_stale (its
+	// alerting.stale_threshold; host_down at 90). On a box without the kernel lane (an older wrapper, a BYO host) the check is refused and logged.
+	go osLeg.KernelAfterBoot(ctx, 0, osupdate.KernelJudge{Wait: osupdate.DefaultKernelJudgeWait})
 
 	// Reconcile (slice 4) runs alongside the hub loop, sharing the per-guest queue
 	// (doc 03 §10). At slice 4 the desired-state provider is empty (no hub serving
@@ -1017,7 +1025,7 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 	// with the local API so a backup and a restore-test can never run together.
 	rtState := backup.NewRestoreTestState(filepath.Join(cfg.OOB.WithDefaults().StateDir, "restore-test-state.json"))
 	heavyOps := &backup.InFlight{}
-	scheduler := buildRestoreTestScheduler(cfg, px, engine, backupStore, rtState, heavyOps, logger)
+	scheduler := buildRestoreTestScheduler(cfg, px, engine, backupStore, rtState, heavyOps, foreignKeys, logger)
 	// R-189: the host report's restore_tests[] must survive an agent restart. The in-memory store
 	// holds only this process's latest run, and under per-archive due-ness the agent will not
 	// re-test an archive it has already proven — so without this the hub can report a tier unproven
@@ -1109,6 +1117,25 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 			}
 			return release, nil
 		}}
+	// R-812 option A: a signed Proxmox package step (`11` §5.10) — ring 1; under the heavy-op gate and the /etc/pve gate.
+	pveExec := osupdate.PVEStepExecutor{Leg: osLeg, Guest: firstGuest(px),
+		Gate: func(ctx context.Context) (func(), error) {
+			release, busy, ok := heavyOps.TryAcquire("os-pve-step")
+			if !ok {
+				return nil, fmt.Errorf("busy: %s", busy)
+			}
+			return release, nil
+		}}
+	// R-836 (`09` §3 decision 172): a signed kernel step STAGES a kernel on a ring-1 box (install + the one-shot flag,
+	// never a reboot — the night leg reboots it on a night the household was told about); under the heavy-op gate.
+	kernelExec := osupdate.KernelStepExecutor{Leg: osLeg, Guest: firstGuest(px),
+		Gate: func(ctx context.Context) (func(), error) {
+			release, busy, ok := heavyOps.TryAcquire("os-kernel-step")
+			if !ok {
+				return nil, fmt.Errorf("busy: %s", busy)
+			}
+			return release, nil
+		}}
 	// Agent v0.143.0 (R-840): the config bundle — the box's root-owned files by a signed job; the wrapper verifies it.
 	bundleExec := osupdate.ConfigUpdateExecutor{Leg: osLeg, URLTemplate: suCfg.URLTemplate, Username: suCfg.Username, Token: suCfg.Token,
 		// The capability probe confirms from the agent's side: `sudo -l` lists every command the new sudoers grants.
@@ -1120,7 +1147,7 @@ func runDaemon(cfg config.Config, logger *slog.Logger, logRing *applog.Ring) int
 			}
 			logger.Warn("osupdate: capability probe after the config bundle", "ok", ok, "total", total, "degraded", strings.Join(names, ","))
 		}}
-	jobsRunner := signedjobs.NewRunner(client, gate, signedjobs.ExecutorChain{wipeExec, decommExec, updateExec, dockerExec, bundleExec}, cfg.Hub.HostID, logger)
+	jobsRunner := signedjobs.NewRunner(client, gate, signedjobs.ExecutorChain{wipeExec, decommExec, updateExec, dockerExec, pveExec, kernelExec, bundleExec}, cfg.Hub.HostID, logger)
 	loop.SetEnvelopeObserver(hub.MultiObserver(desiredSyncer, jobsRunner))
 
 	// Controller-driven escrow ceremony (v0.88.0): static config facts + the LATE-BOUND DR gate —
@@ -1700,7 +1727,7 @@ func primaryBackupTargetOf(cfg config.Config) func() hub.ConfiguredBackupTarget
 // disables the cadence (returns a scheduler that just waits) when the cadence is off or the
 // scratch band / restore storage is invalid — a misconfig must not crash the daemon, and the
 // machinery still works on-demand via --selftest=restore-test.
-func buildRestoreTestScheduler(cfg config.Config, px *proxmox.Client, engine *reconcile.Engine, store *backup.Store, rtState *backup.RestoreTestState, inFlight *backup.InFlight, logger *slog.Logger) *backup.Scheduler {
+func buildRestoreTestScheduler(cfg config.Config, px *proxmox.Client, engine *reconcile.Engine, store *backup.Store, rtState *backup.RestoreTestState, inFlight *backup.InFlight, foreign *backup.ForeignKeyLedger, logger *slog.Logger) *backup.Scheduler {
 	// R-86: this is the EVALUATION interval, not the trigger. What decides a test happens is the
 	// per-archive due-check in internal/backup/restoretest_due.go.
 	cadence := cfg.Backup.RestoreTestEvalInterval()
@@ -1719,6 +1746,9 @@ func buildRestoreTestScheduler(cfg config.Config, px *proxmox.Client, engine *re
 	min, max := cfg.Backup.ScratchBand()
 	target := cfg.Backup.BackupTarget()
 	runner := backup.NewBackupRunner(px, target, "", "felhom restore-test", "", logger)
+	if foreign != nil {
+		runner.SetForeignKeyLedger(foreign) // R-366 slice 2: the pick records archives written with another key
+	}
 	// Every configured tier is a rotation candidate, not just the primary.
 	cfgTiers, _ := cfg.Backup.BackupTiers() // warnings already logged where the tiers are armed
 	tierIDs := make([]string, 0, len(cfgTiers))
@@ -1874,11 +1904,15 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 				return nil, 0, ferr
 			}
 			out := make([]escrow.RetainedBlob, 0, len(resp.Packages))
+			// R-304: every package the hub holds and the code will NOT be tried against — no key material,
+			// over the hub's cap, or malformed here. A refusal may call the code wrong only when this is 0.
+			withheld := resp.UnopenableCount + resp.TruncatedCount
 			for _, p := range resp.Packages {
 				blob, derr := base64.StdEncoding.DecodeString(p.IdentityEscrowB64)
 				if derr != nil || len(blob) == 0 {
 					// One malformed package must not sink the rest — the customer's code may open a
 					// later one, and a skipped entry is strictly better than a refusal we cannot justify.
+					withheld++
 					continue
 				}
 				out = append(out, escrow.RetainedBlob{
@@ -1888,9 +1922,13 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 					Index:          p.Index,
 				})
 			}
-			return out, resp.UnopenableCount, nil
+			return out, withheld, nil
 		},
 	}
+	// R-894: ONE instance — the local API writes it, the host report reads it (2026-10-09: a restart right
+	// after the night backup erased the hub's evidence of it).
+	lastKnownBackups := backup.NewBackupSuccessState(filepath.Join(cfg.OOB.WithDefaults().StateDir, "backup-success-state.json"))
+	collector.SetKnownBackupReporter(lastKnownBackups)
 	srv, err := localapi.NewServer(localapi.Options{
 		EscrowRecovery: escrowRecoverer,
 		ListenAddr:     cfg.LocalAPI.ListenAddr,
@@ -1903,7 +1941,7 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 		Store:          store,
 		// R-894: the newest success per tier on disk — the due-check's fallback when the storage cannot be
 		// read right after a restart. Same state dir as restore-test-state.json.
-		LastKnownBackups: backup.NewBackupSuccessState(filepath.Join(cfg.OOB.WithDefaults().StateDir, "backup-success-state.json")),
+		LastKnownBackups: lastKnownBackups,
 		Storage:          observer,
 		DriveTargets:     driveTargets,                    // Impl-2a: registry+units drives for the /disks view (union w/ Observe storages)
 		Smart:            storage.NewSmartReader(hostOps), // v0.95.0 Fix B: SMART for the union-path drives
@@ -2264,7 +2302,7 @@ func runSelftestRestoreTestDue(ctx context.Context, cfg config.Config, logger *s
 		return 1
 	}
 	rtState := backup.NewRestoreTestState(filepath.Join(cfg.OOB.WithDefaults().StateDir, "restore-test-state.json"))
-	sched := buildRestoreTestScheduler(cfg, px, nil, backup.NewStore(), rtState, &backup.InFlight{}, logger)
+	sched := buildRestoreTestScheduler(cfg, px, nil, backup.NewStore(), rtState, &backup.InFlight{}, nil, logger)
 
 	fmt.Printf("eval_interval=%s settle=%s\n", cfg.Backup.RestoreTestEvalInterval(), cfg.Backup.RestoreTestSettle())
 	start := time.Now()
@@ -2690,7 +2728,6 @@ type escrowCeremonyOpts struct {
 	offline            bool
 	upload             bool
 	identityBundlePath string
-	directivePath      string
 }
 
 // escrowCeremonyOutcome is the shared core's result. R is the ONLY secret; Sum mirrors the
@@ -2749,11 +2786,10 @@ func escrowCeremony(ctx context.Context, cfg config.Config, logger *slog.Logger,
 		return out, &escrowCeremonyErr{kind: "setup", err: fmt.Errorf("PBS key for %q not found (%s): %v", storage, keyPath, err)}
 	}
 
-	// Slice 10D.1: optionally ALSO wrap the identity bundle under the same R, and carry the non-secret
+	// Slice 10D.1: optionally ALSO wrap the identity bundle under the same R. The bundle file is a 0600 secret
-	// directive for the hub. The bundle file is a 0600 secret (tunnel/pbs tokens); the directive is
+	// (tunnel/pbs tokens). The non-secret "directive" that used to ride along is retired (R-105, `09` §3 decision 169:
-	// non-secret (pbs repo/ns, expected fingerprint, tunnel id).
+	// nothing read it; the DR path reads the recipe, tenantsync and the escrow blob).
 	var identity *escrow.IdentityBundle
-	var directive json.RawMessage
 	if opts.identityBundlePath != "" {
 		raw, err := os.ReadFile(opts.identityBundlePath)
 		if err != nil {
@@ -2764,11 +2800,6 @@ func escrowCeremony(ctx context.Context, cfg config.Config, logger *slog.Logger,
 			return out, &escrowCeremonyErr{kind: "setup", err: fmt.Errorf("identity bundle is not valid JSON {tunnel_token,pbs_token}: %v", err)}
 		}
 		identity = &b
-		if opts.directivePath != "" {
-			if d, err := os.ReadFile(opts.directivePath); err == nil && json.Valid(d) {
-				directive = d
-			}
-		}
 	}
 	// S3: auto-inject the offsite WG private key into the escrowed identity when the key file
 	// exists — a NEW escrow run should always capture the live tunnel identity. Field NAME only
@@ -2847,7 +2878,7 @@ func escrowCeremony(ctx context.Context, cfg config.Config, logger *slog.Logger,
 		ResticPwSealed:    resticStaged,
 	}
 	if opts.upload {
-		if err := uploadEscrowBlob(ctx, cfg, res, directive, resticPwSHA256); err != nil {
+		if err := uploadEscrowBlob(ctx, cfg, res, resticPwSHA256); err != nil {
 			// R is minted and the blob self-verified — only the hub leg failed. kind "upload" lets
 			// the text shell keep the pre-extraction order (R surfaced, THEN the failure).
 			return out, &escrowCeremonyErr{kind: "upload", err: err}
@@ -2904,7 +2935,7 @@ func printEscrowTextRBlock(out *escrowCeremonyOutcome) {
 //     NOTHING else there; every human/info line goes to stderr; failures exit non-zero with no
 //     partial JSON. This is the controller-driven ceremony's parse surface (spike §2.3: the text
 //     banner is positionally brittle).
-func runSelftestEscrowCreate(ctx context.Context, cfg config.Config, logger *slog.Logger, storage string, paperkey, offline, upload bool, identityBundlePath, directivePath, outputMode string) int {
+func runSelftestEscrowCreate(ctx context.Context, cfg config.Config, logger *slog.Logger, storage string, paperkey, offline, upload bool, identityBundlePath, outputMode string) int {
 	switch outputMode {
 	case "", "text", "json":
 	default:
@@ -2922,7 +2953,7 @@ func runSelftestEscrowCreate(ctx context.Context, cfg config.Config, logger *slo
 
 	out, cerr := escrowCeremony(ctx, cfg, logger, escrowCeremonyOpts{
 		storage: storage, paperkey: paperkey, offline: offline, upload: upload,
-		identityBundlePath: identityBundlePath, directivePath: directivePath,
+		identityBundlePath: identityBundlePath,
 	})
 	if cerr != nil {
 		switch cerr.kind {
@@ -3105,20 +3136,19 @@ type escrowUploadRequest struct {
 	BlobB64        string `json:"blob_b64"`        // base64 of the opaque R-wrapped blob (ciphertext)
 	KeyFingerprint string `json:"key_fingerprint"` // for operator display only
 	Posture        string `json:"posture"`         // e.g. "zero_knowledge"
-	// Slice 10D.1 — optional DR bundle (identity escrow + non-secret directive). Omitted in slice-7.
+	// Slice 10D.1 — optional identity escrow. Omitted in slice-7. (The `directive` is retired — R-105.)
-	IdentityBlobB64 string          `json:"identity_blob_b64,omitempty"`
+	IdentityBlobB64 string `json:"identity_blob_b64,omitempty"`
-	DirectiveJSON   json.RawMessage `json:"directive,omitempty"`
+	CreatedAt       string `json:"created_at"` // RFC3339
-	CreatedAt       string          `json:"created_at"` // RFC3339
 	// SLICE 3 — sha256 hex of the offsite restic repo password sealed in the identity blob (present only
 	// when a staged password was folded in). Non-reversible hash of a 256-bit random secret — safe to
 	// store/serve; lets the controller VERIFY "the escrow covers the CURRENT key" and auto-confirm.
 	ResticPwSHA256 string `json:"restic_pw_sha256,omitempty"`
 }
 
-// uploadEscrowBlob PUTs the opaque blob (and, for 10D, the identity blob + non-secret directive) to
+// uploadEscrowBlob PUTs the opaque blob (and, for 10D, the identity blob) to
 // the hub, authed with the per-host key. The hub stores ciphertext + non-secret fields; no usable
 // secret leaves the agent.
-func uploadEscrowBlob(ctx context.Context, cfg config.Config, res escrow.CreateResult, directive json.RawMessage, resticPwSHA256 string) error {
+func uploadEscrowBlob(ctx context.Context, cfg config.Config, res escrow.CreateResult, resticPwSHA256 string) error {
 	if cfg.Hub.URL == "" || cfg.Hub.HostID == "" || cfg.Hub.APIKey == "" {
 		return fmt.Errorf("hub not configured (url/host_id/api_key)")
 	}
@@ -3131,7 +3161,6 @@ func uploadEscrowBlob(ctx context.Context, cfg config.Config, res escrow.CreateR
 	}
 	if len(res.IdentityBlob) > 0 {
 		upReq.IdentityBlobB64 = base64.StdEncoding.EncodeToString(res.IdentityBlob)
-		upReq.DirectiveJSON = directive
 	}
 	body, _ := json.Marshal(upReq)
 	url := strings.TrimRight(cfg.Hub.URL, "/") + "/api/v1/hosts/" + cfg.Hub.HostID + "/escrow"

cmd/felhom-agent/r894_wiring_test.go

@@ -12,12 +12,18 @@ import (
 //
 // COMPANION RED-PROOF (observed): delete the `LastKnownBackups:` line from buildLocalAPIServer → this
 // fails with "localapi.Options in buildLocalAPIServer has no LastKnownBackups field". Restored.
+//
+// 2026-10-09: the SAME instance also feeds the host report (collector.SetKnownBackupReporter), so a
+// restart right after a backup no longer erases the hub's evidence of it. The field may name a local
+// variable; the variable must be built by backup.NewBackupSuccessState and be the one handed to the
+// collector. RED-PROOF (observed): drop the SetKnownBackupReporter call → "not handed to the collector".
 func TestR894_LastKnownBackupsIsWiredIntoTheDaemon(t *testing.T) {
 	_, f := parseMain(t)
 	if !callsWithin(f, "main")["runDaemon"] || !callsWithin(f, "runDaemon")["buildLocalAPIServer"] {
 		t.Fatal("main → runDaemon → buildLocalAPIServer is broken — the path this test asserts is not the live one")
 	}
 	var field, built bool
+	var fieldVar, handed string
 	for _, d := range f.Decls {
 		fd, ok := d.(*ast.FuncDecl)
 		if !ok || fd.Name == nil || fd.Name.Name != "buildLocalAPIServer" || fd.Body == nil {
@@ -45,6 +51,28 @@ func TestR894_LastKnownBackupsIsWiredIntoTheDaemon(t *testing.T) {
 					if callsIn(kv.Value)["backup.NewBackupSuccessState"] {
 						built = true
 					}
+					if id, ok := kv.Value.(*ast.Ident); ok {
+						fieldVar = id.Name
+					}
+				}
+			}
+			return true
+		})
+		// a local variable: built by NewBackupSuccessState, and handed to the collector
+		ast.Inspect(fd.Body, func(n ast.Node) bool {
+			switch x := n.(type) {
+			case *ast.AssignStmt:
+				for i, l := range x.Lhs {
+					if id, ok := l.(*ast.Ident); ok && fieldVar != "" && id.Name == fieldVar && i < len(x.Rhs) &&
+						callsIn(x.Rhs[i])["backup.NewBackupSuccessState"] {
+						built = true
+					}
+				}
+			case *ast.CallExpr:
+				if fn, ok := x.Fun.(*ast.SelectorExpr); ok && fn.Sel.Name == "SetKnownBackupReporter" && len(x.Args) == 1 {
+					if id, ok := x.Args[0].(*ast.Ident); ok {
+						handed = id.Name
+					}
 				}
 			}
 			return true
@@ -56,6 +84,9 @@ func TestR894_LastKnownBackupsIsWiredIntoTheDaemon(t *testing.T) {
 	if !built {
 		t.Fatal("LastKnownBackups is not built by backup.NewBackupSuccessState")
 	}
+	if handed == "" || handed != fieldVar {
+		t.Fatalf("the saved backups (%q) are not handed to the collector (SetKnownBackupReporter got %q)", fieldVar, handed)
+	}
 }
 
 func callsIn(n ast.Node) map[string]bool {

cmd/felhom-opsign/main.go

@@ -43,7 +43,7 @@ func main() {
 
 func run() error {
 	var (
-		op        = flag.String("op", "", "op class to sign, e.g. storage_wipe | guest_destroy | decommission | agent_update | os_docker_step | agent_config_update")
+		op        = flag.String("op", "", "op class to sign, e.g. storage_wipe | guest_destroy | decommission | agent_update | os_docker_step | os_pve_step | os_kernel_step | agent_config_update")
 		host      = flag.String("host", "", "target host_id (anti-retarget — the op runs ONLY on this host)")
 		guest     = flag.String("guest", "", "target guest_id (\"\" = host-scoped op)")
 		keyID     = flag.String("key-id", "", "key id of the signing key (must match a pinned agent signer)")

configs/felhom-agent.sudoers

@@ -111,15 +111,17 @@ Cmnd_Alias FELHOM_INTERMEDIARY = \
 #   docker inspect -f *         — container running/health/image (read-only; `*` spans the -f template
 #                                 + container across spaces, spike-confirmed)
 #   systemctl restart <fixed unit> — re-run the golden's bootstrap (the only state change)
-#   tee <FIXED image file>      — WRITE the ref; content is fed on STDIN (no shell, no interpolation),
+#   felhom-priv-apply controller-image <vmid> — WRITE the ref (R-861 (a) A1, `09` §3 decision 165): the ref goes on
-#                                 the agent strict-validates the ref (controllerImageRe) before the write.
+#                                 STDIN to the ROOT wrapper, which requires our registry + repository + an x.y.z tag
+#                                 and writes the guest file itself. The agent's own `tee` grant is GONE: before, a
+#                                 compromised agent could hand the guest's bootstrap ANY image (sudo cannot see stdin).
 # Validated GO: felhom.eu/documentation/audits/SPIKE-controllerswap-narrow-grants-2026-06-29.md.
 Cmnd_Alias FELHOM_CONTROLLERSWAP = \
   /usr/sbin/pct ^exec [0-9]+ -- cat /etc/felhom-controller-image$, \
   /usr/sbin/pct ^exec [0-9]+ -- docker image inspect gitea\.dooplex\.hu/admin/felhom-controller\:[0-9]+\.[0-9]+\.[0-9]+$, \
   /usr/sbin/pct ^exec [0-9]+ -- docker inspect -f .+ (felhom-controller|cloudflared)$, \
   /usr/sbin/pct ^exec [0-9]+ -- systemctl restart felhom-controller-bootstrap\.service$, \
-  /usr/sbin/pct ^exec [0-9]+ -- tee /etc/felhom-controller-image$
+  /usr/local/sbin/felhom-priv-apply ^controller-image [0-9]+$
 
 # Stale-lock recovery (F2-b, v0.49.0). A host reboot DURING a vzdump backup leaves the guest with a
 # `snapshot-delete`/`backup` lock + `onboot:1` then can't start it → the customer box stays DOWN. The

configs/felhom-grub-oneshot-entries.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+# /etc/grub.d/42_felhom_oneshot — the kernel lane's one-shot ENTRIES (R-836, `09` §3 decision 172, `11` §5.11).
+# Installed by the config bundle (felhom-os-apply BUNDLE_FILES), 0755 root. update-grub runs it.
+#
+# One menu entry per installed Proxmox kernel, id `felhom-oneshot-<version>`, booted ONLY when 01_felhom_oneshot found
+# the flag naming it. It is the normal entry plus option C (decision 172): softlockup_panic=1 hardlockup_panic=1
+# hung_task_panic=1 panic=10 — a lockup the kernel can detect becomes a panic, and a panic restarts the box in 10 s into
+# the default (the old kernel). A true dead freeze still needs a person (spike candidate 3 failed on all three boxes).
+# It sorts AFTER 10_linux, so it is never entry 0 and never the default.
+#
+# No vfat ESP at /boot/efi → prints nothing (no flag can name these entries).
+set -e
+prefix="/usr"
+exec_prefix="/usr"
+datarootdir="/usr/share"
+. "$datarootdir/grub/grub-mkconfig_lib"
+esp_uuid=$(findmnt -n -o UUID,FSTYPE /boot/efi 2>/dev/null | awk '$2 == "vfat" { print $1 }')
+[ -n "$esp_uuid" ] || exit 0
+kernels=$(ls /boot/vmlinuz-*-pve 2>/dev/null | sed 's#^/boot/vmlinuz-##' | grep -E '^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$' || true)
+[ -n "$kernels" ] || exit 0
+case "${GRUB_DEVICE}" in
+    /dev/mapper/*|/dev/dm-*|"") root_arg="root=${GRUB_DEVICE}" ;;
+    *) if [ -n "${GRUB_DEVICE_UUID}" ]; then root_arg="root=UUID=${GRUB_DEVICE_UUID}"; else root_arg="root=${GRUB_DEVICE}"; fi ;;
+esac
+[ -n "${GRUB_DEVICE}" ] || root_arg="root=$(findmnt -n -o SOURCE /)"
+rel=$(make_system_path_relative_to_its_root /boot)
+prep=$(prepare_grub_to_access_device "$(${grub_probe:-grub-probe} --target=device /boot)" | sed 's/^/  /')
+for k in $kernels; do
+    [ -f "/boot/initrd.img-$k" ] || continue
+    cat <<EOF
+menuentry 'Felhom one-shot: $k' --class proxmox --id felhom-oneshot-$k {
+  insmod gzio
+$prep
+  echo 'Loading Linux $k (felhom one-shot) ...'
+  linux $rel/vmlinuz-$k $root_arg ro ${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} softlockup_panic=1 hardlockup_panic=1 hung_task_panic=1 panic=10
+  initrd $rel/initrd.img-$k
+}
+EOF
+done

configs/felhom-grub-oneshot.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+# /etc/grub.d/01_felhom_oneshot — the kernel lane's ONE-SHOT boot (R-836, `09` §3 decisions 164 + 172, `11` §5.11).
+# Installed by the config bundle (felhom-os-apply BUNDLE_FILES), 0755 root. update-grub runs it; it prints GRUB script.
+#
+# At boot, GRUB reads `felhom_next` from an environment block on the ESP (vfat — GRUB can rewrite a file there; it
+# cannot on the LVM /boot, R-836), CLEARS it, and — only if it names an installed kernel — boots that kernel's one-shot
+# entry (42_felhom_oneshot) instead of the default. The next boot uses the default again whatever happens: a new kernel
+# that panics comes back on the old one by itself. felhom-os-apply writes the flag (mode apply) and never the default
+# for a new kernel. Measured on the Tester 1 VM, demo-felhom and demo-hp (Secure Boot on):
+# `audits/kernel-spike-2026-10-07/` (candidate 2).
+#
+# No vfat ESP at /boot/efi, or no Proxmox kernel → prints nothing (the box boots exactly as before).
+set -e
+esp_uuid=$(findmnt -n -o UUID,FSTYPE /boot/efi 2>/dev/null | awk '$2 == "vfat" { print $1 }')
+[ -n "$esp_uuid" ] || exit 0
+kernels=$(ls /boot/vmlinuz-*-pve 2>/dev/null | sed 's#^/boot/vmlinuz-##' | grep -E '^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$' || true)
+[ -n "$kernels" ] || exit 0
+cat <<EOF
+# felhom kernel lane: a one-shot kernel named on the ESP, read and cleared before the menu
+insmod part_gpt
+insmod fat
+search --no-floppy --fs-uuid --set=felhom_esp $esp_uuid
+if [ -f (\$felhom_esp)/EFI/felhom/oneshot.env ]; then
+  load_env -f (\$felhom_esp)/EFI/felhom/oneshot.env felhom_next
+  if [ "\${felhom_next}" ]; then
+    set felhom_boot="\${felhom_next}"
+    set felhom_next=
+    save_env -f (\$felhom_esp)/EFI/felhom/oneshot.env felhom_next
+EOF
+for k in $kernels; do
+    printf '    if [ "${felhom_boot}" = "%s" ]; then set default="felhom-oneshot-%s"; fi\n' "$k" "$k"
+done
+cat <<EOF
+  fi
+fi
+EOF

configs/felhom-op.sudoers

@@ -16,8 +16,10 @@ Cmnd_Alias FELHOM_OP_REPAIR = \
   /usr/bin/systemctl reset-failed felhom-sshd, \
   /usr/bin/systemctl restart felhom-sshd, \
   /usr/sbin/pct list, \
-  /usr/sbin/pct start [0-9]*, \
+  /usr/sbin/pct ^start [0-9]+$, \
-  /usr/sbin/pct stop [0-9]*, \
+  /usr/sbin/pct ^stop [0-9]+$, \
-  /usr/sbin/pct unlock [0-9]*
+  /usr/sbin/pct ^unlock [0-9]+$
 
+# R-861 (b) B2 (`09` §3 decision 165, hygiene): one numeric vmid per pct verb, anchored — the old glob `[0-9]*` also
+# matched spaces, so `pct stop 9201 --skiplock 1` passed. Pinned by TestFelhomOpSudoersPctIsExact.
 felhom-op ALL=(root) NOPASSWD: FELHOM_OP_REPAIR

configs/felhom-os-apply

@@ -21,6 +21,11 @@
 # or, for an unsigned ring-0 step, the root-owned TRUST_FILE saying `"ring0_slow_lane": true` (set by hand on the demo
 # boxes only). The agent's own config is NOT trusted for either: the agent can write it. A Docker step also needs
 # `live-restore` ON (R15) — without it every container restarts.
+# Agent v0.151.0 (R-812 option A, `09` §3 decision 163) adds the layer "pve": the HOST's Proxmox USERSPACE packages,
+# lane "slow" only, origin "Proxmox Debian Repository" only, never a kernel / boot / firmware / microcode name (R14 —
+# the kernel is R-836's lane), no removal, no undo, a NEW package only from PVE_NEW_ALLOW, an appliance only (R12), and
+# the same authority as the Docker step (R3: a signed `os_pve_step`, or the root-owned ring-0 mark). Select
+# "pending-pve" (ring 0): every installed Proxmox-origin package with a pending upgrade, minus HOST_SLOW_RE.
 #
 # Modes (plan field "mode"):
 #   inventory   `apt-get update`, then report what is installed (with origin), what is pending, and health.
@@ -88,8 +93,13 @@ OOMCHECK_TIMEOUTS = {"image": 10, "clock": 5, "run": 30, "inspect": 10, "events"
 OOMCHECK_SETTLE = 2
 # Kernel, boot and firmware packages are the SLOW lane on the host whatever their origin (`11` C3, §5.2): a host
 # reboot is needed for them to take effect, and a bad one can stop the box from booting.
+# proxmox-secure-boot-support is the Secure Boot meta-package: its only job is to pull shim-signed and the signed GRUB,
+# so it belongs with them. Measured 2026-10-09 on demo-hp (Secure Boot on): left in the pve lane, its upgrade pulled
+# shim-signed-common, the whole pve step was refused R6, and the night's kernel step was skipped with it
+# (`audits/kernel-night-2026-10-08/`). Pinned by test_ring0_pending_pve_leaves_the_secure_boot_meta_out.
 HOST_SLOW_RE = re.compile(r"^(linux-(image|headers|kbuild|modules|base)|proxmox-kernel|proxmox-default-kernel|pve-kernel|"
-                          r"pve-firmware|firmware-|grub|shim|systemd-boot|intel-microcode|amd64-microcode|efibootmgr)")
+                          r"pve-firmware|firmware-|grub|shim|systemd-boot|intel-microcode|amd64-microcode|efibootmgr|"
+                          r"proxmox-secure-boot-support)")
 # restart_needed() leaves out processes whose cgroup line matches (grep basic regex). Host: the LXC guests' own
 # processes (`0::/lxc/<vmid>/...`) -- NOT lxc-start itself, whose cgroup is `0::/lxc.monitor/<vmid>` (measured
 # 2026-10-04 on demo-felhom: the old pattern "lxc" hid lxc-start with 20 deleted maps, so "reboot needed" stayed false
@@ -100,6 +110,12 @@ HOST_SERVICES = ["pveproxy", "pvedaemon", "pvestatd", "pve-cluster", "felhom-age
 DOCKER_NAMES = ("containerd.io", "docker-buildx-plugin", "docker-ce", "docker-ce-cli", "docker-ce-rootless-extras",
                 "docker-compose-plugin")
 DOCKER_ORIGIN = "Docker CE"
+# The Proxmox package lane (R-812 option A): the origin apt prints for download.proxmox.com, and the ONLY new packages
+# a pve step may add (measured on demo-felhom 2026-10-07: a full upgrade adds proxmox-firewall-data and the kernel;
+# the kernel is refused by R14 whatever this list says).
+PVE_ORIGIN = "Proxmox Debian Repository"
+PVE_NEW_ALLOW = ("proxmox-firewall-data",)
+PVE_SIGNED_OP = "os_pve_step"
 # ROOT-OWNED trust anchors (the installer writes them; the demo boxes got them by hand, R-840). Never the agent's config.
 TRUST_FILE = "/etc/felhom/os-trust.json"          # {"host_id": "...", "ring0_slow_lane": false}
 TRUST_SIGNERS = "/etc/felhom/operator-signers"    # ssh allowed_signers: <key_id> namespaces="felhom-op-v1" <key>
@@ -113,6 +129,32 @@ DAEMON_JSON = "/etc/docker/daemon.json"
 # wrapper restarts exactly the containers that mount one of these paths (never the apps, never the engine).
 DOCKER_SOCKETS = ("/var/run/docker.sock", "/run/docker.sock")
 CRASH_GUARD_STATE = "/var/lib/felhom-crash-guard/state.json"
+# ---------- the kernel lane (R-836, `09` §3 decisions 164 + 172, `11` §5.11) ----------
+# A new kernel boots ONCE through a flag in a GRUB environment block on the ESP (vfat — GRUB can rewrite it there; on
+# the LVM /boot it cannot, R-836). The bundle's two GRUB generators read and clear the flag (01_felhom_oneshot) and
+# give each installed kernel a one-shot entry with the lockup-to-panic options (42_felhom_oneshot, option C). The GRUB
+# default is the kernel the box RUNS, pinned in KERNEL_DEFAULT_CFG; only "kernel-good" (after a healthy one-shot boot)
+# moves it to the new kernel. Measured in the spike on the Tester 1 VM, demo-felhom and demo-hp (Secure Boot on):
+# `audits/kernel-spike-2026-10-07/`.
+KERNEL_OP = "os_kernel_step"
+KERNEL_STATE = "/var/lib/felhom-kernel/state.json"          # 0644 root: the step's phase (the agent reads it)
+KERNEL_DEFAULT_CFG = "/etc/default/grub.d/zz-felhom-kernel-default.cfg"  # sourced last: GRUB_DEFAULT = this kernel
+ONESHOT_SNIPPET = "/etc/grub.d/01_felhom_oneshot"           # bundle-owned: read + clear the flag, pick the entry
+ONESHOT_ENTRIES = "/etc/grub.d/42_felhom_oneshot"           # bundle-owned: the one-shot entries (option C options)
+GRUB_CFG = "/boot/grub/grub.cfg"
+ESP_MOUNT = "/boot/efi"
+ONESHOT_ENV = ESP_MOUNT + "/EFI/felhom/oneshot.env"
+ONESHOT_ARGS = "softlockup_panic=1 hardlockup_panic=1 hung_task_panic=1 panic=10"
+KERNEL_PIN_FILE = "/etc/kernel/proxmox-boot-pin"            # an operator's `proxmox-boot-tool kernel pin` — never fought
+KVER_RE = re.compile(r"^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$")
+KERNEL_IMAGE_RE = re.compile(r"^proxmox-kernel-([0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve)(-signed)?$")
+# the packages a kernel step may UPGRADE (never add): the kernel series meta-package, the default-kernel meta, the boot
+# helper and the firmware the kernel loads. Everything else in HOST_SLOW_RE (grub, shim, microcode, efibootmgr) stays out.
+KERNEL_UPGRADE_RE = re.compile(r"^(proxmox-default-kernel|proxmox-kernel-[0-9]+\.[0-9]+|proxmox-kernel-helper|pve-firmware)$")
+KERNEL_MIN_GAP = 20 * 3600     # never two kernel steps in one night
+KERNEL_MODES = ("kernel-status", "kernel-reboot", "kernel-boot", "kernel-good", "kernel-revert", "kernel-cancel")
+# phases: staged → oneshot → judging → good | reverting → self_reverted | revert_failed; oneshot → fell_back; staged → cancelled
+KERNEL_ACTIVE = ("staged", "oneshot", "judging", "reverting")
 
 # ---------- the config bundle (R-840, agent v0.143.0, `11` §5.4.2) ----------
 # A signed `agent_config_update` job carries {agent_version, bundle_sha256}; the bundle is ONE JSON file built from this
@@ -159,6 +201,10 @@ BUNDLE_FILES = [
     ("/etc/systemd/system/felhom-crash-guard-check.service", "felhom-crash-guard-check.service", 0o644, "unit", "replace"),
     ("/etc/systemd/system/felhom-crash-guard-check.timer", "felhom-crash-guard-check.timer", 0o644, "unit", "replace"),
     ("/etc/felhom/crash-guard.conf", "crash-guard.conf", 0o644, "plain", "if-absent"),
+    # the kernel lane's two GRUB generators (R-836, `11` §5.11): they take effect at the next update-grub, which the
+    # first kernel step runs itself; with no flag on the ESP they change nothing about how the box boots.
+    ("/etc/grub.d/01_felhom_oneshot", "felhom-grub-oneshot.sh", 0o755, "sh", "replace"),
+    ("/etc/grub.d/42_felhom_oneshot", "felhom-grub-oneshot-entries.sh", 0o755, "sh", "replace"),
     ("/etc/systemd/system/felhom-agent.service", "felhom-agent.service", 0o644, "agent-unit", "replace"),
     ("/etc/systemd/system/felhom-agent-rollback.service", "felhom-agent-rollback.service", 0o644, "unit", "replace"),
     ("/etc/systemd/system/felhom-agent.service.d/felhom-agent-limits.conf", "felhom-agent-limits.conf", 0o644, "dropin", "replace"),
@@ -423,7 +469,8 @@ class Apply:
 
     def check_plan(self, plan):
         mode = plan.get("mode", "apply")
-        if mode not in ("apply", "inventory", "health", "facts", "live-restore-on", "bundle", "agent_update", "oom-check"):
+        if mode not in ("apply", "inventory", "health", "facts", "live-restore-on", "bundle", "agent_update", "oom-check") \
+                + KERNEL_MODES:
             raise Refused("R11", f"unknown mode {mode!r}")
         if mode == "agent_update":
             if plan.get("layer") != "host":
@@ -434,12 +481,18 @@ class Apply:
                 raise Refused("R11", "bundle is a host-layer mode")
             return mode, "host", 0, "bundle"
         layer = plan.get("layer")
-        if layer not in ("guest", "host", "docker"):
+        if layer not in ("guest", "host", "docker", "pve", "kernel"):
-            raise Refused("R12", f"layer {layer!r} is not guest, host or docker")
+            raise Refused("R12", f"layer {layer!r} is not guest, host, docker, pve or kernel")
+        if (mode in KERNEL_MODES) != (layer == "kernel" and mode not in ("apply", "health")):
+            raise Refused("R11", f"mode {mode!r} does not fit layer {layer!r}")
         lane = plan.get("lane", "fast")
         if layer == "docker" and lane != "slow":
             raise Refused("R3", "the Docker engine is the slow lane (`11` §5.8); a fast-lane Docker plan is refused")
-        if layer != "docker" and lane != "fast":
+        if layer == "pve" and lane != "slow":
+            raise Refused("R3", "the Proxmox packages are the slow lane (`11` §5.10); a fast-lane pve plan is refused")
+        if layer == "kernel" and lane != "slow":
+            raise Refused("R3", "the kernel is the slow lane (`11` §5.11); a fast-lane kernel plan is refused")
+        if layer not in ("docker", "pve", "kernel") and lane != "fast":
             raise Refused("R3", f"the {layer} layer has no slow lane in this release (kernel, Proxmox: `11` §8 step 6)")
         if mode == "facts" and layer != "host":
             raise Refused("R11", "facts is a host-layer mode (it reads the host and the guest)")
@@ -447,10 +500,12 @@ class Apply:
             raise Refused("R11", "live-restore-on is a guest-layer mode")
         if mode == "oom-check" and layer != "docker":
             raise Refused("R11", "oom-check is a docker-layer mode (it checks the guest's Docker engine)")
-        if plan.get("undo") and layer != "docker":
+        if plan.get("undo") and layer != "docker":  # the pve layer has no undo in this release (R-812 option A)
             raise Refused("R5", "an undo (downgrade) exists only for the Docker layer, inside a signed job")
         vmid = plan.get("vmid")
-        if not isinstance(vmid, int) or isinstance(vmid, bool) or vmid <= 0:
+        if layer == "kernel" and mode in KERNEL_MODES and mode != "kernel-reboot" and vmid == 0:
+            pass  # after a boot the guest may not run (that is what is judged); these modes never touch it
+        elif not isinstance(vmid, int) or isinstance(vmid, bool) or vmid <= 0:
             raise Refused("R11", f"vmid must be a positive integer, got {vmid!r}")
         rid = plan.get("release_id", "")
         if not isinstance(rid, str) or not re.match(r"^[A-Za-z0-9._:-]{1,80}$", rid):
@@ -458,17 +513,24 @@ class Apply:
         if plan.get("allow_new"):
             raise Refused("R6", "allow_new is a slow-lane field; the fast lane never adds a package")
         select = plan.get("select", "listed")
-        if select not in ("listed", "pending-fast", "pending-docker"):
+        if select not in ("listed", "pending-fast", "pending-docker", "pending-pve", "pending-kernel"):
             raise Refused("R11", f"unknown select {select!r}")
         if (select == "pending-docker") != (layer == "docker" and select != "listed"):
             if select == "pending-docker" or layer == "docker":
                 raise Refused("R11", f"select {select!r} does not fit layer {layer!r}")
+        if (select == "pending-pve") != (layer == "pve" and select != "listed"):
+            raise Refused("R11", f"select {select!r} does not fit layer {layer!r}")
+        if (select == "pending-kernel") != (layer == "kernel" and select != "listed"):
+            raise Refused("R11", f"select {select!r} does not fit layer {layer!r}")
+        ek = plan.get("expect_kver")
+        if ek is not None and (layer != "kernel" or not isinstance(ek, str) or not KVER_RE.match(ek)):
+            raise Refused("R11", f"expect_kver {ek!r} is not a kernel version of the kernel layer")
         pk = plan.get("packages", [])
         if not isinstance(pk, list):
             raise Refused("R11", "packages must be a list")
         if mode == "apply" and select == "listed" and not pk:
             raise Refused("R11", "packages must be a non-empty list in apply mode (select listed)")
-        if select in ("pending-fast", "pending-docker") and pk:
+        if select in ("pending-fast", "pending-docker", "pending-pve", "pending-kernel") and pk:
             raise Refused("R11", f"select {select} takes no package list")
         seen = set()
         for e in pk:
@@ -488,6 +550,19 @@ class Apply:
                 continue
             if n in DOCKER_NAMES:
                 raise Refused("R2", f"{n} is a Docker package — the slow lane (`11` §5.8), never in a {layer} plan")
+            if layer == "kernel":
+                if o != PVE_ORIGIN:
+                    raise Refused("R2", f"{n}: origin {o!r} is not {PVE_ORIGIN!r} (the kernel layer)")
+                if not (KERNEL_UPGRADE_RE.match(n) or KERNEL_IMAGE_RE.match(n)):
+                    raise Refused("R23", f"{n} is not a kernel package (a kernel image, the kernel meta-packages, "
+                                         f"proxmox-kernel-helper or pve-firmware)")
+                continue
+            if layer == "pve":
+                if o != PVE_ORIGIN:
+                    raise Refused("R2", f"{n}: origin {o!r} is not {PVE_ORIGIN!r} (the pve layer)")
+                if HOST_SLOW_RE.match(n):
+                    raise Refused("R14", f"{n} is a kernel / boot / firmware package — never the pve lane (R-836)")
+                continue
             if o not in FAST_ORIGINS:
                 raise Refused("R2", f"{n}: origin {o!r} is not Debian / Debian-Security (the fast lane, `11` C3)")
             if layer == "host" and HOST_SLOW_RE.match(n):
@@ -630,12 +705,13 @@ class Apply:
         now = self.r.now()
         self.r.write_nonces({k: v for k, v in seen.items() if v > now})
 
-    def docker_authority(self, plan):
+    def docker_authority(self, plan, op_name=SIGNED_OP):
-        """R3 for the docker layer: returns (who, undo). A signed job binds the EXACT package list and the undo flag."""
+        """R3 for the docker (and, op_name os_pve_step, the pve) layer: returns (who, undo). A signed job binds the EXACT
+        package list and the undo flag."""
         trust = self.load_trust()
         signed = plan.get("signed")
         if signed:
-            params = self.verify_signed(signed, trust)
+            params = self.verify_signed(signed, trust, op_name=op_name)
             want = sorted(f"{e.get('name')}={e.get('version')}" for e in params.get("packages") or [])
             got = sorted(f"{e['name']}={e['version']}" for e in plan.get("packages", []))
             if not want or want != got:
@@ -649,7 +725,7 @@ class Apply:
             raise Refused("R3", "an undo (downgrade) needs a signed operator job")
         if trust.get("ring0_slow_lane") is True:
             return "ring0", False
-        raise Refused("R3", "a Docker step needs a signed operator job (ring 1) or this box's root-owned ring-0 mark")
+        raise Refused("R3", f"a {self.layer} slow-lane step needs a signed operator job (ring 1) or this box's root-owned ring-0 mark")
 
     def live_restore(self):
         rc, out, _ = self.g(["docker", "info", "--format", "{{.LiveRestoreEnabled}}"], timeout=60)
@@ -737,6 +813,17 @@ class Apply:
             return v or "unknown"
         h = {"debian": first(["cat", "/etc/debian_version"]), "kernel_running": first(["uname", "-r"])}
         h["kernel_next_boot"], h["kernel_next_boot_source"] = self.kernel_next_boot()
+        try:
+            # the kernel lane (R-836): the default and the one-shot flag, read from grub.cfg and the ESP themselves
+            kv = Kernel(self, {}).view()
+            kv["setup_problems"] = Kernel(self, {}).setup_problems()
+            h["kernel_lane"] = kv
+            if kv.get("flag"):
+                h["kernel_next_boot"], h["kernel_next_boot_source"] = kv["flag"], "felhom one-shot flag (once; then the default)"
+            elif kv.get("default") not in (None, "unknown"):
+                h["kernel_next_boot"], h["kernel_next_boot_source"] = kv["default"], "grub.cfg default"
+        except Exception as e:  # never cost the System page its other facts
+            h["kernel_lane"] = {"error": str(e)[:200]}
         rc, out, _ = self.r.host(["apt-mark", "showhold"], 60)
         h["held"] = sorted(out.split()) if rc == 0 else None
         try:
@@ -795,8 +882,8 @@ class Apply:
 
     # ---------- target helpers ----------
     def x(self, argv, timeout=1800):
-        """Run in the TARGET layer: the guest via pct exec, or the host directly."""
+        """Run in the TARGET layer: the guest via pct exec, or the host directly (host, pve and kernel)."""
-        if self.layer == "host":
+        if self.layer in ("host", "pve", "kernel"):
             return self.r.host(argv, timeout)
         return self.r.guest(self.vmid, argv, timeout)  # guest and docker both live in the customer guest
 
@@ -891,7 +978,7 @@ class Apply:
     def restart_needed(self):
         """Processes still mapping deleted files, OUTSIDE containers (C11). Guest: outside docker; host: outside the
         LXC guests (the host's /proc shows guest processes too)."""
-        skip = RESTART_SKIP_CGROUP["host" if self.layer == "host" else "guest"]
+        skip = RESTART_SKIP_CGROUP["host" if self.layer in ("host", "pve", "kernel") else "guest"]
         script = ('for p in /proc/[0-9]*; do grep -q "(deleted)" $p/maps 2>/dev/null || continue; '
                   'grep -q "%s" $p/cgroup 2>/dev/null && continue; echo "${p#/proc/} $(cat $p/comm 2>/dev/null)"; done' % skip)
         rc, out, _ = self.x(["sh", "-c", script], timeout=120)
@@ -965,8 +1052,12 @@ class Apply:
             return Bundle(self).from_plan(plan)
         if self.mode == "agent_update":
             return self.agent_update(plan)
-        if self.layer == "host":
+        if self.layer in ("host", "pve", "kernel"):
             self.check_appliance()
+        if self.layer == "kernel" and self.mode != "health":
+            # the kernel lane's own modes (R-836): most of them run while the guest is still starting after a boot, so
+            # the guest check is the stage's and the reboot's own (Kernel.run), not every mode's
+            return Kernel(self, plan).run()
         self.check_guest(self.vmid)
         log = self.r.log
         if self.mode == "live-restore-on":
@@ -976,6 +1067,9 @@ class Apply:
             self.report["oom_check"] = self.oom_check()
             return 0
         self.who, self.allow_downgrade = ("fast", False)
+        if self.layer == "pve" and self.mode == "apply":
+            self.who, self.allow_downgrade = self.docker_authority(plan, op_name=PVE_SIGNED_OP)
+            self.report["authority"] = self.who
         if self.layer == "docker" and self.mode == "apply":
             self.who, self.allow_downgrade = self.docker_authority(plan)
             if self.live_restore() != "true":
@@ -988,7 +1082,7 @@ class Apply:
         log(f"os-apply: START release={plan.get('release_id')} layer={self.layer}" +
             (f":{self.vmid}" if self.layer != "host" else "") +
             f" lane={plan.get('lane', 'fast')} mode={self.mode} select={self.select} packages={len(plan.get('packages', []))}" +
-            (f" authority={self.who}{' UNDO' if self.allow_downgrade else ''}" if self.layer == "docker" else ""))
+            (f" authority={self.who}{' UNDO' if self.allow_downgrade else ''}" if self.layer in ("docker", "pve") else ""))
         if self.apt_lock_held():
             raise Refused("R9", f"another apt/dpkg holds the lock on the {self.layer}")
         self.report["health_before"] = self.health()
@@ -1012,6 +1106,8 @@ class Apply:
         if self.layer == "docker":
             rc_v, out_v, _ = self.g(["docker", "version", "--format", "{{.Server.Version}}"], timeout=60)
             self.report["docker_engine"] = out_v.strip() if rc_v == 0 and out_v.strip() else "unknown"
+        if self.layer == "pve":
+            self.report["pve_manager"] = self.pve_manager()
         self.report["reboot_scanned"] = "reboot_needed" in self.report
         self.report["health_after"] = self.health()
         if self.layer == "docker" and self.mode == "apply":
@@ -1161,10 +1257,26 @@ class Apply:
         return [{"name": p["name"], "version": p["to"], "origin": DOCKER_ORIGIN} for p in pend
                 if p["from"] is not None and p["name"] in DOCKER_NAMES and self.origin_name(p["origin"]) == {DOCKER_ORIGIN}]
 
+    def pending_pve(self):
+        """Ring 0 (select pending-pve): the newest pending version of each INSTALLED Proxmox-origin package, never a
+        kernel / boot / firmware / microcode name (HOST_SLOW_RE, R-836's lane), never another origin."""
+        rc, pend, remv, _ = self.simulate(["dist-upgrade"])
+        return [{"name": p["name"], "version": p["to"], "origin": PVE_ORIGIN} for p in pend
+                if p["from"] is not None and not HOST_SLOW_RE.match(p["name"]) and p["name"] not in DOCKER_NAMES
+                and self.origin_name(p["origin"]) == {PVE_ORIGIN}]
+
+    def pve_manager(self):
+        """pveversion's pve-manager version ("unknown" when it cannot be read)."""
+        rc, out, _ = self.r.host(["pveversion"], 60)
+        m = re.match(r"^pve-manager/([^/\s]+)", out.strip()) if rc == 0 else None
+        return m.group(1) if m else "unknown"
+
     def origin_ok(self, origin):
         o = self.origin_name(origin)
         if self.layer == "docker":
             return o == {DOCKER_ORIGIN}
+        if self.layer == "pve":
+            return o == {PVE_ORIGIN}
         return bool(o & set(FAST_ORIGINS))
 
     def apply(self, plan):
@@ -1173,6 +1285,8 @@ class Apply:
             packages = plan["packages"]
         elif self.select == "pending-docker":
             packages = self.pending_docker()
+        elif self.select == "pending-pve":
+            packages = self.pending_pve()
         else:
             packages = self.pending_fast()
         cmp_op = "ne" if self.allow_downgrade else "gt"
@@ -1221,6 +1335,11 @@ class Apply:
                 raise Refused("R4", f"the plan would remove {', '.join(remv[:5])}")
             want = dict(upgrade)
             for p in sim:
+                if p["from"] is None and self.layer == "pve" and p["name"] in PVE_NEW_ALLOW and self.origin_ok(p["origin"]) \
+                        and not HOST_SLOW_RE.match(p["name"]):
+                    self.r.log(f"os-apply: NEW {p['name']}={p['to']} (on the pve lane's allow-list)")
+                    self.report.setdefault("added", []).append({"name": p["name"], "version": p["to"]})
+                    continue
                 if p["from"] is None:
                     raise Refused("R6", f"the plan would add a package that is not installed: {p['name']}")
                 if p["name"] not in want:
@@ -1231,7 +1350,7 @@ class Apply:
                     raise Refused("R5", f"{p['name']} would be downgraded {p['from']} -> {p['to']}")
                 if not self.origin_ok(p["origin"]):
                     raise Refused("R2", f"{p['name']} would come from {p['origin']}, not the {self.layer} layer's origin")
-                if self.layer == "host" and HOST_SLOW_RE.match(p["name"]):
+                if self.layer in ("host", "pve") and HOST_SLOW_RE.match(p["name"]):
                     raise Refused("R14", f"{p['name']} is a kernel / boot / firmware package — the host's slow lane")
             need = self.download_bytes(args)
             free = self.free_bytes()
@@ -1314,6 +1433,422 @@ class Apply:
         self.x(APT_ENV + ["apt-get", "-q", "update"], timeout=600)
 
 
+def _iso(t):
+    return time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime(t))
+
+
+def _parse_iso(s):
+    try:
+        return calendar.timegm(time.strptime(s, "%Y-%m-%dT%H:%M:%SZ"))
+    except (TypeError, ValueError):
+        return None
+
+
+class Kernel:
+    """The kernel lane (R-836, `09` §3 decisions 164 + 172, `11` §5.11). Refusal codes: R3 (authority), R4 (removal),
+    R6 (a package outside the step), R8 (space), R9 (locks), R12 (appliance), R20 (the box's boot setup cannot do a
+    one-shot), R21 (the crash guard is tripped or saw an unclean boot within its window), R22 (the step's phase does not
+    allow this mode), R23 (the kernel set is not one exact new kernel).
+
+    Modes (plan "mode", layer "kernel", lane "slow"):
+      apply          STAGE: install the kernel set, keep the GRUB default on the kernel the box runs, write the flag.
+                     Never reboots. select "pending-kernel" (ring 0, the root-owned mark) or "listed" (a signed
+                     os_kernel_step). expect_kver: the kernel the hub told the household about — any other is R23.
+      kernel-reboot  a STAGED step's reboot (the night leg, after the household was told): phase oneshot, then reboot.
+      kernel-boot    after a boot: what became of the step (judging | fell_back | self_reverted | revert_failed).
+      kernel-good    the one-shot boot was healthy: the new kernel becomes the GRUB default.
+      kernel-revert  the one-shot boot was NOT healthy: reboot ONCE into the old kernel (still the default).
+      kernel-cancel  drop a staged step: clear the flag (the package stays installed, the default never moved).
+      kernel-status  read only."""
+
+    def __init__(self, apply, plan):
+        self.a, self.r, self.plan = apply, apply.r, plan
+        self.report = apply.report
+        self.log = apply.r.log
+
+    # ---------- reading the box ----------
+    def running(self):
+        rc, out, _ = self.r.host(["uname", "-r"], 30)
+        v = out.strip() if rc == 0 else ""
+        return v if KVER_RE.match(v) else ""
+
+    def state(self):
+        try:
+            s = json.loads(self.r.read_file(KERNEL_STATE))
+            return s if isinstance(s, dict) else {}
+        except (OSError, ValueError):
+            return {}
+
+    def save_state(self, s):
+        s["updated_at"] = _iso(self.r.now())
+        self.r.put_file(KERNEL_STATE, (json.dumps(s, indent=2, sort_keys=True) + "\n").encode(), 0o644)
+
+    def flag(self):
+        """The one-shot flag: the kernel named, "" when the env block holds none, None when there is no env block."""
+        rc, out, _ = self.r.host(["grub-editenv", ONESHOT_ENV, "list"], 30)
+        if rc != 0:
+            return None
+        for l in out.splitlines():
+            if l.startswith("felhom_next="):
+                return l.split("=", 1)[1].strip()
+        return ""
+
+    def grub_cfg(self):
+        try:
+            return self.r.read_file(GRUB_CFG)
+        except OSError:
+            return ""
+
+    @staticmethod
+    def default_kver(cfg):
+        """The kernel grub.cfg boots by default (00_header's `set default=`), or "unknown"."""
+        m = re.search(r'^\s*set default="(?:gnulinux-advanced-[^>"]*>)?gnulinux-([0-9][^"]*?-pve)-advanced-[^"]*"', cfg, re.M)
+        return m.group(1) if m else "unknown"
+
+    @staticmethod
+    def entry_id(cfg, kver):
+        """The GRUB_DEFAULT value that names kver's normal entry, read from grub.cfg itself (10_linux's ids)."""
+        sub = re.search(r"\$menuentry_id_option '(gnulinux-advanced-[^']+)'", cfg)
+        m = re.search(r"\$menuentry_id_option '(gnulinux-" + re.escape(kver) + r"-advanced-[^']+)'", cfg)
+        if not m:
+            return None
+        return f"{sub.group(1)}>{m.group(1)}" if sub else m.group(1)
+
+    def setup_problems(self):
+        """R20: why this box cannot do a one-shot boot (empty = it can). Measured shape: UEFI, a vfat ESP at /boot/efi,
+        /boot on the root filesystem, GRUB with fat + loadenv, the bundle's two generators, no hand pin."""
+        why = []
+        if not self.r.lexists("/sys/firmware/efi"):
+            why.append("the box does not boot UEFI")
+        rc, out, _ = self.r.host(["findmnt", "-n", "-o", "FSTYPE", ESP_MOUNT], 30)
+        if rc != 0 or out.strip() != "vfat":
+            why.append(f"{ESP_MOUNT} is not a mounted vfat ESP ({out.strip() or 'not mounted'})")
+        rc, out, _ = self.r.host(["findmnt", "-n", "-o", "TARGET", "/boot"], 30)
+        if rc == 0 and out.strip():
+            why.append("/boot is a separate filesystem (the one-shot entries assume /boot on the root filesystem)")
+        for m in ("fat", "loadenv"):
+            if not self.r.lexists(f"/usr/lib/grub/x86_64-efi/{m}.mod"):
+                why.append(f"GRUB has no {m} module")
+        for p in (ONESHOT_SNIPPET, ONESHOT_ENTRIES):
+            if not self.r.lexists(p):
+                why.append(f"{p} is missing (the config bundle installs it)")
+        if self.r.lexists(KERNEL_PIN_FILE):
+            why.append("a kernel is pinned by hand (proxmox-boot-tool kernel pin) — the lane never fights it")
+        return why
+
+    def guard(self):
+        try:
+            return json.loads(self.r.read_file(CRASH_GUARD_STATE))
+        except (OSError, ValueError):
+            return None
+
+    def check_guard(self):
+        """R21: a kernel step only on a box whose crash guard is armed and saw no unclean boot within its window — so
+        the step's own reboots (clean), one crash and one self-revert (clean) can never reach the 3rd unclean boot that
+        leaves the box off (`11` §5.9). Pinned by test_felhom_crash_guard KernelStepCannotLeaveTheBoxOff."""
+        g = self.guard()
+        if not isinstance(g, dict):
+            raise Refused("R21", f"no crash guard state ({CRASH_GUARD_STATE}) — a kernel step needs the guard")
+        if g.get("tripped") or not g.get("armed"):
+            raise Refused("R21", "the crash guard is tripped — no kernel step until it re-arms")
+        if (g.get("unclean_boots_in_window") or 0) > 0:
+            raise Refused("R21", f"{g.get('unclean_boots_in_window')} unclean boot(s) within the guard's window — wait")
+
+    def view(self, st=None, cfg=None):
+        st = self.state() if st is None else st
+        cfg = self.grub_cfg() if cfg is None else cfg
+        return {"running": self.running() or "unknown", "default": self.default_kver(cfg), "flag": self.flag(),
+                "phase": st.get("phase", "none"), "from": st.get("from"), "to": st.get("to"),
+                "step_id": st.get("step_id"), "self_revert_used": bool(st.get("self_revert_used")), "vmid": st.get("vmid"),
+                "staged_at": st.get("staged_at"), "rebooted_at": st.get("rebooted_at"),
+                "result_at": st.get("result_at"), "reason": st.get("reason")}
+
+    # ---------- writing the box ----------
+    def write_default(self, kver):
+        """Pin the GRUB default to kver's normal entry, regenerate grub.cfg, and PROVE it (the default read back)."""
+        cfg = self.grub_cfg()
+        eid = self.entry_id(cfg, kver)
+        if not eid:
+            raise Refused("R20", f"grub.cfg has no normal entry for {kver}")
+        body = ("# felhom kernel lane (R-836, `11` §5.11) — written by felhom-os-apply; the kernel that booted healthily\n"
+                f'GRUB_DEFAULT="{eid}"\n')
+        self.r.put_file(KERNEL_DEFAULT_CFG, body.encode(), 0o644)
+        rc, out, err = self.r.host(["update-grub"], 300)
+        got = self.default_kver(self.grub_cfg())
+        if rc != 0 or got != kver:
+            raise Refused("R20", f"update-grub rc={rc}: the default reads {got}, not {kver}: {(out + err).strip()[-200:]}")
+        self.log(f"os-apply: KERNEL default = {kver} (proved from grub.cfg)")
+
+    def set_flag(self, kver):
+        self.r.host(["mkdir", "-p", os.path.dirname(ONESHOT_ENV)], 30)
+        if self.flag() is None:
+            rc, out, err = self.r.host(["grub-editenv", ONESHOT_ENV, "create"], 30)
+            if rc != 0:
+                raise Refused("R20", f"cannot create the one-shot env block on the ESP: {(out + err).strip()[-200:]}")
+        rc, out, err = self.r.host(["grub-editenv", ONESHOT_ENV, "set", f"felhom_next={kver}"], 30)
+        if rc != 0 or self.flag() != kver:
+            raise Refused("R20", f"the one-shot flag did not read back as {kver}: {(out + err).strip()[-200:]}")
+
+    def clear_flag(self):
+        if self.flag():
+            self.r.host(["grub-editenv", ONESHOT_ENV, "unset", "felhom_next"], 30)
+
+    def reboot(self, why):
+        self.log(f"os-apply: KERNEL REBOOT — {why}")
+        rc, out, err = self.r.host(["systemctl", "reboot"], 60)
+        self.report["reboot_rc"] = rc
+        if rc != 0:
+            self.report["failed"] = {"rc": 3, "step": "reboot", "reason": (out + err).strip()[-200:]}
+            return 3
+        return 0
+
+    # ---------- the modes ----------
+    def run(self):
+        mode = self.a.mode
+        self.report["kernel_mode"] = mode
+        if mode == "kernel-status":
+            v = self.view()
+            v["setup_problems"] = self.setup_problems()
+            self.report["kernel"] = v
+            return 0
+        fn = {"apply": self.stage, "kernel-reboot": self.reboot_staged, "kernel-boot": self.after_boot,
+              "kernel-good": self.good, "kernel-revert": self.revert, "kernel-cancel": self.cancel}[mode]
+        rc = fn()
+        self.report["kernel"] = self.view()
+        return rc
+
+    def phase_is(self, st, *phases):
+        if st.get("phase") not in phases:
+            raise Refused("R22", f"the kernel step is {st.get('phase', 'none')!r}, not {' or '.join(phases)} — "
+                                 f"{self.a.mode} does not apply")
+
+    def stage(self):
+        a = self.a
+        st = self.state()
+        if st.get("phase") in KERNEL_ACTIVE:
+            raise Refused("R22", f"a kernel step is already {st['phase']} ({st.get('from')} -> {st.get('to')})")
+        last = _parse_iso(st.get("staged_at"))
+        if last is not None and self.r.now() - last < KERNEL_MIN_GAP:
+            raise Refused("R22", "a kernel step was staged within the last 20 hours — never two in one night")
+        why = self.setup_problems()
+        if why:
+            raise Refused("R20", "; ".join(why))
+        self.check_guard()
+        a.check_guest(a.vmid)
+        who, _ = a.docker_authority(self.plan, op_name=KERNEL_OP)
+        self.report["authority"] = who
+        old = self.running()
+        if not old:
+            raise Refused("R20", "the running kernel is not a Proxmox kernel version")
+        self.log(f"os-apply: START release={self.plan.get('release_id')} layer=kernel lane=slow mode=apply "
+                 f"select={a.select} authority={who} running={old}")
+        if a.apt_lock_held():
+            raise Refused("R9", "another apt/dpkg holds the lock on the host")
+        self.report["health_before"] = a.health()
+        a.repair()
+        rc, out, err = a.x(APT_ENV + ["apt-get", "-q", "update"], timeout=600)
+        if rc != 0:
+            raise Refused("R7", f"apt-get update failed on the host: {(out + err).strip().splitlines()[-1:]}")
+        inst = a.installed()
+        if a.select == "pending-kernel":
+            _, pend, _, _ = a.simulate(["dist-upgrade"])
+            want = [(p["name"], p["to"]) for p in pend if p["from"] is not None and KERNEL_UPGRADE_RE.match(p["name"])
+                    and a.origin_name(p["origin"]) == {PVE_ORIGIN}]
+        else:
+            want = [(e["name"], e["version"]) for e in self.plan["packages"]]
+        # upgrades of installed names (never a downgrade), and at most the listed new kernel image
+        args, upg = [], {}
+        for n, v in want:
+            if n in inst:
+                if a.dpkg_cmp(v, "gt", inst[n]):
+                    upg[n] = v
+                    args.append(f"{n}={v}")
+            elif KERNEL_IMAGE_RE.match(n):
+                args.append(f"{n}={v}")
+            else:
+                raise Refused("R6", f"{n} is not installed and is not a kernel image")
+        if not args:
+            self.report["upgraded"], self.report["outcome_hint"] = [], "nothing"
+            self.log("os-apply: DONE rc=0 upgraded=0 (no pending kernel)")
+            return 0
+        rc, sim, remv, text = a.simulate(["install", "--no-install-recommends"] + args)
+        if rc != 0:
+            raise Refused("R7", "the simulation failed: " + (text.strip().splitlines()[-1] if text.strip() else ""))
+        if remv:
+            raise Refused("R4", f"the kernel step would remove {', '.join(remv[:5])}")
+        images = []
+        listed = dict(want)
+        for p in sim:
+            if a.origin_name(p["origin"]) != {PVE_ORIGIN}:
+                raise Refused("R2", f"{p['name']} would come from {p['origin']}, not {PVE_ORIGIN!r}")
+            m = KERNEL_IMAGE_RE.match(p["name"])
+            if p["from"] is None:
+                if not m:
+                    raise Refused("R6", f"the kernel step would add {p['name']}, which is not a kernel image")
+                if a.select == "listed" and listed.get(p["name"]) != p["to"]:
+                    raise Refused("R23", f"the kernel step would add {p['name']}={p['to']}, not the signed set")
+                images.append((m.group(1), p["to"]))
+                continue
+            if p["name"] not in upg or p["to"] != upg[p["name"]]:
+                raise Refused("R6", f"the kernel step would touch {p['name']} ({p['to']}), which is not in the step")
+            if not a.dpkg_cmp(p["to"], "gt", p["from"]):
+                raise Refused("R5", f"{p['name']} would be downgraded {p['from']} -> {p['to']}")
+        if len(images) > 1:
+            raise Refused("R23", f"the kernel step would add {len(images)} kernels — one at a time")
+        # the target kernel: the new image, else the series meta-package's version (its image is already installed)
+        if images:
+            new = images[0][0]
+            if images[0][1] + "-pve" != new:
+                raise Refused("R23", f"the image version {images[0][1]} does not name the kernel {new}")
+        else:
+            metas = [(n, v) for n, v in upg.items() if re.match(r"^proxmox-kernel-[0-9]+\.[0-9]+$", n)]
+            if len(metas) != 1:
+                self.report["upgraded"], self.report["outcome_hint"] = [], "nothing"
+                self.log("os-apply: DONE rc=0 upgraded=0 (the pending set names no kernel to boot)")
+                return 0
+            new = metas[0][1] + "-pve"
+        if not KVER_RE.match(new) or not a.dpkg_cmp(new[:-4], "gt", old[:-4]):
+            raise Refused("R23", f"the kernel {new} is not newer than the running {old}")
+        ek = self.plan.get("expect_kver")
+        if ek and ek != new:
+            raise Refused("R23", f"the step would boot {new}, but the household was told about {ek}")
+        need = a.download_bytes(["install", "--no-install-recommends"] + args)
+        free = a.free_bytes()
+        if free >= 0 and free < max(MIN_FREE, 3 * need):
+            raise Refused("R8", f"free space {free} B is below max(500 MB, 3 x download {need} B)")
+        # 1. the default = the kernel the box RUNS (it booted healthily), proved from grub.cfg BEFORE the install
+        default_before = self.default_kver(self.grub_cfg())
+        self.write_default(old)
+        # 2. install (the kernel's own postinst runs update-grub; our default file keeps the default on `old`)
+        t0 = time.time()
+        rc, out, err = a.x(APT_ENV + ["apt-get", "-y", "-q"] + DPKG_OPTS + ["install", "--no-install-recommends"] + args)
+        a.x(["apt-get", "clean"])
+        if rc != 0:
+            _, aud, _ = a.x(["dpkg", "--audit"])
+            self.report["failed"] = {"rc": rc, "step": "install", "dpkg_audit": (aud.strip().splitlines() or ["clean"])[0],
+                                     "tail": (out + err).strip().splitlines()[-3:]}
+            self.log(f"os-apply: FAILED rc={rc} step=install (the default stays {old}; no flag written)")
+            return 3
+        self.report["upgraded"] = [{"name": x.split("=", 1)[0], "version": x.split("=", 1)[1]} for x in args]
+        self.report["seconds"] = round(time.time() - t0, 1)
+        # 3. prove: the image is there, the default is still `old`, the one-shot entry for `new` exists
+        cfg = self.grub_cfg()
+        if f"felhom-oneshot-{new}" not in cfg or self.default_kver(cfg) != old:
+            self.r.host(["update-grub"], 300)
+            cfg = self.grub_cfg()
+        for f in (f"/boot/vmlinuz-{new}", f"/boot/initrd.img-{new}"):
+            if not self.r.lexists(f):
+                self.report["failed"] = {"rc": 3, "step": "verify", "reason": f"{f} is missing after the install"}
+                return 3
+        if f"felhom-oneshot-{new}" not in cfg or "felhom_next" not in cfg:
+            self.report["failed"] = {"rc": 3, "step": "verify", "reason": f"grub.cfg has no one-shot entry for {new}"}
+            return 3
+        if self.default_kver(cfg) != old:
+            self.report["failed"] = {"rc": 3, "step": "verify",
+                                     "reason": f"the install moved the default to {self.default_kver(cfg)} — no flag written"}
+            return 3
+        # 4. the flag — the ONLY thing that makes the next boot use `new`, and only once
+        self.set_flag(new)
+        self.save_state({"phase": "staged", "step_id": self.plan.get("release_id"), "from": old, "to": new, "vmid": a.vmid,
+                         "staged_at": _iso(self.r.now()), "authority": who, "default_before": default_before,
+                         "packages": self.report["upgraded"], "self_revert_used": False})
+        self.report["reboot_needed"] = True
+        self.log(f"os-apply: KERNEL STAGED {old} -> {new} (default {old}, one-shot flag {new}); upgraded={len(args)} "
+                 f"seconds={self.report['seconds']}")
+        return 0
+
+    def reboot_staged(self):
+        st = self.state()
+        self.phase_is(st, "staged")
+        if self.flag() != st.get("to"):
+            raise Refused("R22", f"the one-shot flag reads {self.flag()!r}, not {st.get('to')!r}")
+        if self.running() != st.get("from"):
+            raise Refused("R22", f"the box runs {self.running()!r}, not the step's old kernel {st.get('from')!r}")
+        cfg = self.grub_cfg()
+        if self.default_kver(cfg) != st["from"] or f"felhom-oneshot-{st['to']}" not in cfg:
+            raise Refused("R20", "grub.cfg no longer keeps the old default with a one-shot entry for the new kernel")
+        if self.setup_problems():
+            raise Refused("R20", "; ".join(self.setup_problems()))
+        self.check_guard()
+        self.a.check_guest(self.a.vmid)
+        st["health_before"] = self.a.health()
+        st["phase"], st["rebooted_at"] = "oneshot", _iso(self.r.now())
+        self.save_state(st)
+        return self.reboot(f"one-shot boot of {st['to']} (the default stays {st['from']})")
+
+    def after_boot(self):
+        st = self.state()
+        ph, run = st.get("phase"), self.running()
+        old, new = st.get("from"), st.get("to")
+        event = "none"
+        if ph in ("oneshot", "staged", "judging") and run == new and new:
+            if ph != "judging":
+                st["phase"], st["judging_since"], event = "judging", _iso(self.r.now()), "judging"
+            else:
+                event = "judging"
+        elif ph in ("oneshot", "judging") and run == old:
+            # the new kernel did not come up, or crashed: GRUB already booted the default (the old kernel)
+            self.clear_flag()
+            st["phase"], st["result_at"], event = "fell_back", _iso(self.r.now()), "fell_back"
+            st["reason"] = "the box came back on the old kernel by itself (the new one did not boot, or crashed)"
+        elif ph == "reverting" and run == old:
+            st["phase"], st["result_at"], event = "self_reverted", _iso(self.r.now()), "self_reverted"
+        elif ph == "reverting" and run == new:
+            st["phase"], st["result_at"], event = "revert_failed", _iso(self.r.now()), "revert_failed"
+            st["reason"] = "the self-revert came back on the NEW kernel — never retried (one self-revert per step)"
+        if event not in ("none",) and st.get("phase") != ph:
+            self.save_state(st)
+            self.log(f"os-apply: KERNEL AFTER-BOOT {ph} -> {st['phase']} running={run} ({old} -> {new})")
+        self.report["kernel_event"] = event
+        if event == "judging":
+            self.report["health_before"] = st.get("health_before")  # the agent judges the boot against it
+        return 0
+
+    def good(self):
+        st = self.state()
+        self.phase_is(st, "judging")
+        if self.running() != st.get("to"):
+            raise Refused("R22", f"the box runs {self.running()!r}, not the new kernel {st.get('to')!r}")
+        try:
+            self.write_default(st["to"])
+        except Refused:
+            # put the old default back — the box must never be left without a proved default
+            self.write_default(st["from"])
+            raise
+        self.clear_flag()
+        st["phase"], st["result_at"] = "good", _iso(self.r.now())
+        self.save_state(st)
+        self.log(f"os-apply: KERNEL GOOD {st['to']} is the default now (was {st['from']})")
+        return 0
+
+    def revert(self):
+        st = self.state()
+        self.phase_is(st, "judging")
+        if st.get("self_revert_used"):
+            raise Refused("R22", "this kernel step already used its one self-revert")
+        if self.running() != st.get("to"):
+            raise Refused("R22", f"the box runs {self.running()!r}, not the new kernel {st.get('to')!r}")
+        self.clear_flag()
+        cfg = self.grub_cfg()
+        if self.default_kver(cfg) != st.get("from"):
+            raise Refused("R20", f"the GRUB default reads {self.default_kver(cfg)}, not the old {st.get('from')} — "
+                                 f"no self-revert into an unknown kernel")
+        reason = self.plan.get("reason")
+        st["reason"] = reason[:300] if isinstance(reason, str) else "the one-shot boot was not healthy"
+        st["self_revert_used"], st["phase"], st["reverted_at"] = True, "reverting", _iso(self.r.now())
+        self.save_state(st)
+        return self.reboot(f"self-revert to {st['from']}: {st['reason']}")
+
+    def cancel(self):
+        st = self.state()
+        self.phase_is(st, "staged")
+        self.clear_flag()
+        st["phase"], st["result_at"], st["reason"] = "cancelled", _iso(self.r.now()), "cancelled before the reboot"
+        self.save_state(st)
+        self.log(f"os-apply: KERNEL CANCELLED {st.get('to')} (installed, never the default; flag cleared)")
+        return 0
+
+
 class Bundle:
     """The config bundle (R-840, `11` §5.4.2): every root-owned file the installer's step 5 writes, installed as ONE
     signed unit. Every check runs before the first write; a failed write or a failed self-check puts every previous

configs/felhom-priv-apply

@@ -17,6 +17,8 @@ Verbs (each one sudoers line, exact-match pattern):
   wg                       /var/lib/felhom-agent/wg/wg-felhom.conf -> /etc/wireguard/wg-felhom.conf (0600)
   sshd-config              /var/lib/felhom-agent/felhom-sshd/sshd_config -> /etc/felhom-sshd/sshd_config
   sshd-key                 /var/lib/felhom-agent/felhom-sshd/authorized_keys.felhom-op -> /etc/felhom-sshd/authorized_keys/felhom-op
+  controller-image <vmid>  the ref on STDIN -> /etc/felhom-controller-image INSIDE guest <vmid> (R-861 (a) A1): only
+                           our registry + our repository + an x.y.z tag; the agent no longer has a `tee` grant
   --self-check             prints "felhom-priv-apply ok verbs=..." (the bundle's self-check)
 
 Exit codes: 0 installed (or already identical), 2 usage, 3 refused (content or source), 4 install failed.
@@ -39,7 +41,14 @@ WG_SRC, WG_DEST = STATE + "/wg/wg-felhom.conf", "/etc/wireguard/wg-felhom.conf"
 SSHD_SRC, SSHD_DEST = STATE + "/felhom-sshd/sshd_config", "/etc/felhom-sshd/sshd_config"
 KEY_SRC, KEY_DEST = STATE + "/felhom-sshd/authorized_keys.felhom-op", "/etc/felhom-sshd/authorized_keys/felhom-op"
 MAX_BYTES = 64 * 1024
-VERBS = ("unit", "dnsmasq", "wg", "sshd-config", "sshd-key")
+VERBS = ("unit", "dnsmasq", "wg", "sshd-config", "sshd-key", "controller-image")
+# R-861 (a) A1 (`09` §3 decision 165): the SAME pattern as the agent's controllerImageRe (internal/localapi/
+# controllerswap.go) — a compromised agent cannot hand the guest's bootstrap any other image. Pinned by
+# configs/test_felhom_priv_apply.py ControllerImage.
+CONTROLLER_IMAGE_RE = re.compile(r"^gitea\.dooplex\.hu/admin/felhom-controller:[0-9]+\.[0-9]+\.[0-9]+$")
+CONTROLLER_IMAGE_FILE = "/etc/felhom-controller-image"
+CONTROLLER_IMAGE_MAX = 256
+VMID_RE = re.compile(r"^[0-9]{1,9}$")
 
 UNIT_NAME_RE = re.compile(r"^mnt-[A-Za-z0-9_.\\-]+\.(mount|automount)$")
 DNSMASQ_TMP_RE = re.compile(r"^/tmp/felhom-resolver-[0-9]+\.conf$")
@@ -123,6 +132,16 @@ class Host:
                 pass
             raise
 
+    def read_stdin(self, limit):
+        return sys.stdin.buffer.read(limit + 1)
+
+    def write_guest_image(self, vmid, data):
+        """As root: `pct exec <vmid> -- tee <the fixed file>` with the checked ref on stdin (no shell)."""
+        r = subprocess.run(["/usr/sbin/pct", "exec", str(vmid), "--", "tee", CONTROLLER_IMAGE_FILE],
+                           input=data, stdout=subprocess.DEVNULL, stderr=subprocess.PIPE, timeout=60)
+        if r.returncode != 0:
+            raise OSError(f"pct exec {vmid} tee exited {r.returncode}: {r.stderr.decode(errors='replace').strip()[:200]}")
+
     def log(self, line):
         print(line, file=sys.stderr)
         try:
@@ -377,6 +396,34 @@ def plan(argv):
     raise Refused("A1", f"wrong arguments for {v}")
 
 
+def controller_image(rest, host):
+    """R-861 (a) A1: read the ref on stdin, check it, write it INSIDE the guest as root."""
+    try:
+        if len(rest) != 1 or not VMID_RE.match(rest[0]):
+            raise Refused("A1", "usage: felhom-priv-apply controller-image <vmid>  (the ref on stdin)")
+        raw = host.read_stdin(CONTROLLER_IMAGE_MAX)
+        if len(raw) > CONTROLLER_IMAGE_MAX:
+            raise Refused("I1", f"the image ref is longer than {CONTROLLER_IMAGE_MAX} bytes")
+        try:
+            text = raw.decode("ascii")
+        except UnicodeDecodeError:
+            raise Refused("I1", "the image ref is not ASCII")
+        ref = text[:-1] if text.endswith("\n") else text
+        if not CONTROLLER_IMAGE_RE.match(ref) or "\n" in ref:
+            raise Refused("I1", "the image ref is not gitea.dooplex.hu/admin/felhom-controller:<x.y.z>")
+    except Refused as e:
+        host.log(f"felhom-priv-apply: REFUSED [{e.rule}] controller-image {' '.join(rest)[:40]}: {e.reason}")
+        return 2 if e.rule == "A1" else 3
+    vmid = int(rest[0])
+    try:
+        host.write_guest_image(vmid, (ref + "\n").encode())
+    except (OSError, subprocess.SubprocessError) as e:
+        host.log(f"felhom-priv-apply: FAILED controller-image {vmid}: {e}")
+        return 4
+    host.log(f"felhom-priv-apply: WROTE controller-image {vmid} {ref}")
+    return 0
+
+
 def main(argv, host=None):
     host = host or Host()
     if argv == ["--self-check"]:
@@ -396,6 +443,8 @@ def main(argv, host=None):
             return 3
         print("OK")
         return 0
+    if argv and argv[0] == "controller-image":
+        return controller_image(argv[1:], host)
     try:
         verb, src, dest, mode, checker = plan(argv)
         data = host.read_source(src)

configs/test_felhom_crash_guard.py

@@ -139,5 +139,62 @@ class Guard(unittest.TestCase):
         self.assertEqual(mode, 0o644)
 
 
+class KernelStepCannotLeaveTheBoxOff(unittest.TestCase):
+    """R-836 / `11` §5.11 Part B 4: a kernel step's planned reboot, one crash and one self-revert cannot add up to the
+    box staying off. The wrapper starts a step only when the guard is armed with NO unclean boot in its window
+    (felhom-os-apply Kernel.check_guard, R21); the planned reboot and the self-revert are orderly (`systemctl reboot` —
+    the clean-stop marker); so the step adds at most ONE unclean boot, and the box stays off only after the LIMIT-th
+    (3rd) within the hour. Red-proof: audits/kernel-lane-2026-10-07/A/redproof.txt."""
+
+    def setUp(self):
+        self.d = tempfile.TemporaryDirectory()
+        self.e = FakeEnv(self.d.name)
+        cg.main(["x", "boot"], self.e)
+        s = self.e.state()
+        self.assertTrue(s["armed"])
+        self.assertEqual(s["unclean_boots_in_window"], 0, "the wrapper's precondition (R21)")
+
+    def tearDown(self):
+        self.d.cleanup()
+
+    def planned(self, minutes):
+        cg.main(["x", "clean-stop"], self.e)
+        self.e.t += minutes * 60
+        cg.main(["x", "boot"], self.e)
+
+    def crash(self, minutes):
+        self.e.t += minutes * 60
+        cg.main(["x", "boot"], self.e)
+
+    def test_planned_reboot_one_crash_one_self_revert(self):
+        self.planned(2)      # the step's one-shot reboot (orderly)
+        self.crash(3)        # the new kernel crashes after the guard ran; the box restarts (panic=10)
+        self.planned(2)      # the self-revert (orderly)
+        s = self.e.state()
+        self.assertFalse(s["tripped"], s)
+        self.assertTrue(s["armed"])
+        self.assertEqual(self.e.panic(), 10, "the box still restarts after a crash")
+        self.assertEqual(s["unclean_boots_in_window"], 1, "the step added exactly one unclean boot")
+
+    def test_a_panic_before_userspace_is_not_even_counted(self):
+        # the one-shot kernel panics before the guard's unit runs (measured: rdinit= and init= missing): the planned
+        # reboot's clean-stop marker is still there when the old kernel boots, so this boot counts as clean.
+        cg.main(["x", "clean-stop"], self.e)
+        self.e.t += 120      # the panicking boot: no userspace, the guard never ran
+        cg.main(["x", "boot"], self.e)
+        s = self.e.state()
+        self.assertEqual(s["unclean_boots_in_window"], 0, s)
+        self.assertEqual(self.e.panic(), 10)
+
+    def test_the_box_stays_off_only_after_two_more_crashes_than_the_step_makes(self):
+        self.planned(2)
+        self.crash(3)        # the step's one crash
+        self.planned(2)      # the self-revert
+        self.crash(5)        # an UNRELATED crash within the hour: the guard trips (the 3rd would leave it off)
+        s = self.e.state()
+        self.assertTrue(s["tripped"])
+        self.assertEqual(s["unclean_boots_in_window"], 2, "two unclean boots: one from the step, one not")
+
+
 if __name__ == "__main__":
     unittest.main()

configs/test_felhom_os_apply.py

@@ -232,6 +232,8 @@ class Fake:
             return (0, self.daemon_json, "") if self.daemon_json is not None else (1, "", "No such file")
         if cmd == "cat" and a[1] == "/etc/debian_version":
             return 0, "13.7\n", ""
+        if cmd == "pveversion":
+            return 0, f"pve-manager/{self.installed.get('pve-manager', '9.2.2')}/abcdef (running kernel: 7.0.14-20-pve)\n", ""
         if cmd == "uname":
             return 0, "7.0.14-20-pve\n", ""
         if cmd == "apt-mark":
@@ -284,7 +286,7 @@ class Fake:
                 n, v = x.split("=", 1)
                 if v not in self.avail(n):
                     return 100, "", f"E: Version '{v}' for '{n}' was not found"
-                origin = "Docker CE:trixie" if n in osapply.DOCKER_NAMES else SEC if n == "openssl" else DEB
+                origin = getattr(self, "origins", {}).get(n) or ("Docker CE:trixie" if n in osapply.DOCKER_NAMES else SEC if n == "openssl" else DEB)
                 out += f"Inst {n} [{self.installed[n]}] ({v} {origin} [amd64])\n"
         out += "".join(l + "\n" for l in self.extra_sim)
         return 0, out, ""
@@ -1324,5 +1326,684 @@ class OOMCheck(unittest.TestCase):
         self.assertEqual((rc, rep["refused"]["code"]), (2, "R11"), rep)
 
 
+PVE = "Proxmox Debian Repository:stable"
+PVE_SET = [{"name": "pve-manager", "version": "9.2.21", "origin": "Proxmox Debian Repository"},
+           {"name": "libpve-common-perl", "version": "9.1.9", "origin": "Proxmox Debian Repository"}]
+
+
+def pve_fake(signed=None, ring0=False):
+    f = Fake()
+    f.installed.update({"pve-manager": "9.2.2", "libpve-common-perl": "9.1.1", "proxmox-kernel-helper": "9.0.4"})
+    f.live["pve-manager"] = {"9.2.21", "9.2.2"}
+    f.live["libpve-common-perl"] = {"9.1.9", "9.1.1"}
+    f.origins = {"pve-manager": PVE, "libpve-common-perl": PVE, "proxmox-kernel-helper": PVE, "shim-signed": PVE,
+                 "proxmox-firewall-data": PVE}
+    f.plan = {"release_id": "os-pve-t1", "layer": "pve", "lane": "slow", "vmid": 9201, "mode": "apply",
+              "packages": [dict(p) for p in PVE_SET]}
+    if ring0:
+        f.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": True})
+    if signed is not None:
+        f.plan["signed"] = signed
+    return f
+
+
+class PVELane(unittest.TestCase):
+    """R-812 option A (`09` §3 decision 163): the host's Proxmox USERSPACE packages, slow lane, no kernel / boot /
+    firmware / microcode (R14), no removal, a new package only from PVE_NEW_ALLOW. Red-proof: audits/day-2026-10-07/B/."""
+
+    def refused(self, f, code):
+        rc, rep = run(f)
+        self.assertEqual(rc, 2, rep)
+        self.assertEqual(rep["refused"]["code"], code, rep)
+        self.assertEqual(f.installed["pve-manager"], "9.2.2", "nothing may be installed on a refusal")
+        return rep
+
+    # THE RED TEST (design-R-812 §5): before the pve layer existed this plan was refused R12.
+    def test_pve_manager_plan_is_installed_on_the_host(self):
+        f = pve_fake(signed=signed_job(packages=PVE_SET, op="os_pve_step"))
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(f.installed["pve-manager"], "9.2.21")
+        self.assertEqual(rep["authority"], "signed")
+        self.assertEqual(rep["pve_manager"], "9.2.21", "pveversion after the step is reported")
+        inst = [c for c in f.calls if c[0] == "host" and "install" in c[1] and "-s" not in c[1] and "-f" not in c[1]
+                and "--print-uris" not in c[1]]
+        self.assertTrue(inst, "the pve layer installs on the HOST")
+        self.assertFalse([c for c in f.calls if c[0] == "guest" and "install" in c[2]], "nothing installed in the guest")
+        self.assertEqual(sorted(rep["health_after"]["host_services"]), sorted(osapply.HOST_SERVICES))
+
+    def test_kernel_in_a_pve_plan_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.plan["packages"].append({"name": "proxmox-kernel-7.0", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"})
+        self.refused(f, "R14")
+
+    def test_shim_in_a_pve_plan_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.plan["packages"].append({"name": "shim-signed", "version": "1.47+pmx1", "origin": "Proxmox Debian Repository"})
+        self.refused(f, "R14")
+
+    def test_kernel_pulled_in_by_the_simulation_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.installed["proxmox-kernel-helper"] = "9.0.4"
+        f.extra_sim = ["Inst proxmox-kernel-helper [9.0.4] (9.0.6 Proxmox Debian Repository:stable [all])"]
+        self.refused(f, "R6")  # not in the plan — refused before the name check; R14 below when it IS in the plan
+        g = pve_fake(ring0=True)
+        g.live["proxmox-kernel-helper"] = {"9.0.6"}
+        g.plan["packages"] = [dict(PVE_SET[0])]
+        g.extra_sim = ["Inst proxmox-kernel-helper [9.0.4] (9.0.6 Proxmox Debian Repository:stable [all])"]
+        # a kernel-helper the plan did not name is R6; the R14 name check covers a listed one (test above)
+        self.refused(g, "R6")
+
+    def test_debian_package_in_a_pve_plan_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.plan["packages"].append({"name": "libc6", "version": "2.41-12+deb13u4", "origin": "Debian"})
+        self.refused(f, "R2")
+
+    def test_debian_origin_in_the_pve_simulation_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.origins["libpve-common-perl"] = DEB
+        self.refused(f, "R2")
+
+    def test_docker_package_in_a_pve_plan_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.plan["packages"].append({"name": "docker-ce", "version": "5:29.8.2-1~debian.13~trixie", "origin": "Proxmox Debian Repository"})
+        self.refused(f, "R2")
+
+    def test_pve_in_the_fast_lane_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.plan["lane"] = "fast"
+        self.refused(f, "R3")
+
+    def test_no_authority_is_refused(self):
+        self.refused(pve_fake(), "R3")
+
+    def test_docker_signed_op_does_not_authorize_a_pve_step(self):
+        self.refused(pve_fake(signed=signed_job(packages=PVE_SET, op="os_docker_step")), "R3")
+
+    def test_pve_on_a_byo_box_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.files[osapply.INSTALL_STATE] = json.dumps({"mode": "byo"})
+        self.refused(f, "R12")
+
+    def test_unlisted_new_package_is_refused(self):
+        f = pve_fake(ring0=True)
+        f.extra_sim = ["Inst proxmox-new-thing (1.0 Proxmox Debian Repository:stable [all])"]
+        self.refused(f, "R6")
+
+    def test_allow_listed_new_package_is_accepted(self):
+        f = pve_fake(ring0=True)
+        f.extra_sim = ["Inst proxmox-firewall-data (0.1 Proxmox Debian Repository:stable [all])"]
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(f.installed["pve-manager"], "9.2.21")
+
+    def test_allow_new_is_never_an_open_door_in_the_fast_lane(self):
+        f = Fake()
+        f.plan["layer"] = "host"
+        f.extra_sim = ["Inst proxmox-firewall-data (0.1 Proxmox Debian Repository:stable [all])"]
+        rc, rep = run(f)
+        self.assertEqual((rc, rep["refused"]["code"]), (2, "R6"), rep)
+
+    def test_undo_is_refused(self):
+        f = pve_fake(signed=signed_job(packages=PVE_SET, op="os_pve_step"))
+        f.plan["undo"] = True
+        self.refused(f, "R5")
+
+    def test_ring0_pending_pve_takes_only_installed_proxmox_userspace(self):
+        f = pve_fake(ring0=True)
+        f.plan["select"], f.plan["packages"] = "pending-pve", []
+        f.installed.update({"linux-image-amd64": "6.12.1", "tailscale": "1.102.2"})
+        f.pending_sim = [
+            "Inst pve-manager [9.2.2] (9.2.21 Proxmox Debian Repository:stable [amd64])",
+            "Inst libpve-common-perl [9.1.1] (9.1.9 Proxmox Debian Repository:stable [all])",
+            "Inst proxmox-kernel-helper [9.0.4] (9.0.6 Proxmox Debian Repository:stable [all])",
+            "Inst proxmox-kernel-7.0.14-20-pve-signed (7.0.14-20 Proxmox Debian Repository:stable [amd64])",
+            "Inst proxmox-firewall-data (0.1 Proxmox Debian Repository:stable [all])",
+            "Inst libc6 [2.41-12+deb13u3] (2.41-12+deb13u4 Debian:13.7/stable [amd64])",
+            "Inst tailscale [1.102.2] (1.102.5 Tailscale:pkgs.tailscale.com [amd64])",
+        ]
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["authority"], "ring0")
+        self.assertEqual(sorted(u["name"] for u in rep["upgraded"]), ["libpve-common-perl", "pve-manager"],
+                         "pending-pve: installed, Proxmox-origin, never kernel/boot/firmware, never Debian or other origins")
+        self.assertEqual(f.installed["libc6"], "2.41-12+deb13u3")
+
+    # 2026-10-09, demo-hp (Secure Boot on): proxmox-secure-boot-support's upgrade pulls shim-signed-common; in the pve
+    # plan that refused the whole step (R6) and skipped the night's kernel step. It is a boot-chain package: left out.
+    # RED-PROOF: drop proxmox-secure-boot-support from HOST_SLOW_RE -> it is in the plan -> this test fails.
+    def test_ring0_pending_pve_leaves_the_secure_boot_meta_out(self):
+        f = pve_fake(ring0=True)
+        f.plan["select"], f.plan["packages"] = "pending-pve", []
+        f.installed.update({"proxmox-secure-boot-support": "9.0.1"})
+        f.pending_sim = [
+            "Inst pve-manager [9.2.2] (9.2.21 Proxmox Debian Repository:stable [amd64])",
+            "Inst proxmox-secure-boot-support [9.0.1] (9.0.2 Proxmox Debian Repository:stable [all])",
+            "Inst shim-signed-common [1.48+pmx1+16.1-1+pmx1] (1.51+pmx1+16.1-2+pmx1 Proxmox Debian Repository:stable [all])",
+        ]
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(sorted(u["name"] for u in rep["upgraded"]), ["pve-manager"])
+        self.assertEqual(f.installed["proxmox-secure-boot-support"], "9.0.1")
+
+    def test_select_pending_pve_needs_the_pve_layer(self):
+        f = Fake()
+        f.plan["layer"], f.plan["select"], f.plan["packages"] = "host", "pending-pve", []
+        rc, rep = run(f)
+        self.assertEqual((rc, rep["refused"]["code"]), (2, "R11"), rep)
+
+
+# ---------- the kernel lane (R-836, `09` §3 decision 172, `11` §5.11) ----------
+U = "1af1fcc6-639c-416b-a7e5-c4470d41a502"
+OLD, NEW = "7.0.2-6-pve", "7.0.14-22-pve"
+KERNEL_SET = [{"name": "proxmox-kernel-7.0", "version": "7.0.14-22", "origin": "Proxmox Debian Repository"},
+              {"name": "proxmox-kernel-7.0.14-22-pve-signed", "version": "7.0.14-22", "origin": "Proxmox Debian Repository"}]
+
+
+class KFake(Fake):
+    """A Proxmox host with GRUB on UEFI: /boot on the root LV, a vfat ESP, the bundle's two generators. update-grub is
+    emulated like the real 10_linux: WITHOUT the felhom default file the NEWEST kernel becomes the default (measured,
+    R-836 — that is the defect the lane exists for); with it, the kernel it names."""
+
+    def __init__(self):
+        super().__init__()
+        self.running = OLD
+        self.boot = {OLD}
+        self.efi, self.esp_fs, self.boot_mount, self.mods, self.snippets, self.pin = True, "vfat", "", True, True, False
+        self.env = None          # None = no env block on the ESP; else {"felhom_next": ...}
+        self.tree = {}           # files put_file wrote
+        self.reboots = []
+        self.update_grubs = 0
+        self.grub_runs_in_postinst = True
+        self.installed.update({"proxmox-kernel-7.0": "7.0.2-6", "proxmox-default-kernel": "2.1.0",
+                               "pve-firmware": "3.18-3", "proxmox-kernel-7.0.2-6-pve-signed": "7.0.2-6",
+                               "pve-manager": "9.2.21"})
+        self.live.update({"proxmox-kernel-7.0": {"7.0.14-22", "7.0.2-6"},
+                          "proxmox-kernel-7.0.14-22-pve-signed": {"7.0.14-22"},
+                          "proxmox-kernel-7.0.14-23-pve-signed": {"7.0.14-23"},
+                          "pve-firmware": {"3.18-7", "3.18-3"}})
+        self.origins = {}
+        self.kernel_pending = ["Inst pve-firmware [3.18-3] (3.18-7 Proxmox Debian Repository:stable [all])",
+                               "Inst proxmox-kernel-7.0.14-22-pve-signed (7.0.14-22 Proxmox Debian Repository:stable [amd64])",
+                               "Inst proxmox-kernel-7.0 [7.0.2-6] (7.0.14-22 Proxmox Debian Repository:stable [amd64])",
+                               "Inst pve-manager [9.2.21] (9.2.22 Proxmox Debian Repository:stable [amd64])",
+                               "Inst libc6 [2.41-12+deb13u3] (2.41-12+deb13u4 Debian:13.7/stable [amd64])"]
+        self.plan = {"release_id": "kernel-t1", "layer": "kernel", "lane": "slow", "vmid": 9201, "mode": "apply",
+                     "select": "pending-kernel", "packages": []}
+        self.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": True})
+        self.files[osapply.CRASH_GUARD_STATE] = json.dumps({"armed": True, "tripped": False, "unclean_boots_in_window": 0})
+        self.cfg = self.render()
+
+    # -- GRUB --
+    def newest(self):
+        best = None
+        for k in self.boot:
+            if best is None or dpkg_cmp(k[:-4], "gt", best[:-4]):
+                best = k
+        return best
+
+    def render(self):
+        d = self.tree.get(osapply.KERNEL_DEFAULT_CFG)
+        if d:
+            dflt = re.search(r'GRUB_DEFAULT="([^"]+)"', d).group(1)
+        else:
+            dflt = f"gnulinux-advanced-{U}>gnulinux-{self.newest()}-advanced-{U}"
+        cfg = ('if [ "${next_entry}" ] ; then\n   set default="${next_entry}"\nelse\n'
+               f'   set default="{dflt}"\nfi\n'
+               f"submenu 'Advanced options' $menuentry_id_option 'gnulinux-advanced-{U}' {{\n")
+        for k in sorted(self.boot):
+            cfg += f"  menuentry 'Proxmox VE, with Linux {k}' $menuentry_id_option 'gnulinux-{k}-advanced-{U}' {{ }}\n"
+        cfg += "}\n"
+        if self.snippets:
+            cfg += "### BEGIN /etc/grub.d/01_felhom_oneshot ###\nload_env felhom_next\n"
+            cfg += "".join(f"menuentry 'Felhom one-shot: {k}' --id felhom-oneshot-{k} {{ }}\n" for k in sorted(self.boot))
+        return cfg
+
+    def lexists(self, p):
+        if p == "/sys/firmware/efi":
+            return self.efi
+        if p.startswith("/usr/lib/grub/x86_64-efi/"):
+            return self.mods
+        if p in (osapply.ONESHOT_SNIPPET, osapply.ONESHOT_ENTRIES):
+            return self.snippets
+        if p == osapply.KERNEL_PIN_FILE:
+            return self.pin
+        m = re.match(r"^/boot/(vmlinuz|initrd\.img)-(.+)$", p)
+        if m:
+            return m.group(2) in self.boot
+        return p in self.tree
+
+    def put_file(self, path, data, mode):
+        self.tree[path] = data.decode()
+
+    def read_file(self, p):
+        if p == osapply.GRUB_CFG:
+            return self.cfg
+        if p in self.tree:
+            return self.tree[p]
+        return super().read_file(p)
+
+    def host(self, argv, timeout=600, stdin=None):
+        if argv[0] == "uname":
+            self.calls.append(("host", argv))
+            return 0, self.running + "\n", ""
+        if argv[0] == "findmnt":
+            self.calls.append(("host", argv))
+            if argv[-1] == osapply.ESP_MOUNT:
+                return (0, self.esp_fs + "\n", "") if self.esp_fs else (1, "", "")
+            return (0, self.boot_mount + "\n", "") if self.boot_mount else (1, "", "")
+        if argv[0] == "grub-editenv":
+            self.calls.append(("host", argv))
+            if argv[2] == "list":
+                return (1, "", "no such file") if self.env is None else \
+                    (0, "".join(f"{k}={v}\n" for k, v in self.env.items()), "")
+            if argv[2] == "create":
+                self.env = {}
+                return 0, "", ""
+            if argv[2] == "set":
+                k, v = argv[3].split("=", 1)
+                self.env[k] = v
+                return 0, "", ""
+            if argv[2] == "unset":
+                self.env.pop(argv[3], None)
+                return 0, "", ""
+        if argv[0] == "update-grub":
+            self.calls.append(("host", argv))
+            self.update_grubs += 1
+            self.cfg = self.render()
+            return 0, "", ""
+        if argv[0] == "mkdir":
+            self.calls.append(("host", argv))
+            return 0, "", ""
+        if argv[:2] == ["systemctl", "reboot"]:
+            self.calls.append(("host", argv))
+            self.reboots.append(self.running)
+            return 0, "", ""
+        return super().host(argv, timeout, stdin)
+
+    def emulate(self, argv):
+        a = [x for x in argv if not re.match(r"^[A-Z_]+=", x) and x != "env"]
+        if a[0] == "apt-get" and "install" in a and "-s" not in a and "--print-uris" not in a and "-f" not in a:
+            if self.install_rc:
+                return self.install_rc, "", "E: boom"
+            for x in a:
+                if "=" in x and not x.startswith("-") and "::" not in x:
+                    n, v = x.split("=", 1)
+                    self.installed[n] = v
+                    m = re.match(r"^proxmox-kernel-[0-9]+\.[0-9]+$", n)
+                    if m:
+                        self.installed[f"proxmox-kernel-{v}-pve-signed"] = v
+                    if m or osapply.KERNEL_IMAGE_RE.match(n):
+                        self.boot.add(v + "-pve")
+            if self.grub_runs_in_postinst:
+                self.cfg = self.render()   # the kernel's postinst runs update-grub (zz-update-grub)
+            return 0, "Setting up proxmox-kernel ...\n", ""
+        return super().emulate(argv)
+
+    def sim(self, a):
+        if "--print-uris" in a:
+            return 0, "", ""
+        if "dist-upgrade" in a:
+            return 0, "\n".join(self.kernel_pending) + "\n", ""
+        out, named = "", set()
+        for x in a:
+            if "=" in x and not x.startswith("-") and "::" not in x:
+                named.add(x.split("=", 1)[0])
+        for x in a:
+            if "=" in x and not x.startswith("-") and "::" not in x:
+                n, v = x.split("=", 1)
+                if v not in self.avail(n):
+                    return 100, "", f"E: Version '{v}' for '{n}' was not found"
+                o = self.origins.get(n, PVE)
+                out += f"Inst {n} [{self.installed[n]}] ({v} {o} [amd64])\n" if n in self.installed else f"Inst {n} ({v} {o} [amd64])\n"
+                if re.match(r"^proxmox-kernel-[0-9]+\.[0-9]+$", n):
+                    img = f"proxmox-kernel-{v}-pve-signed"
+                    if img not in self.installed and img not in named:
+                        out += f"Inst {img} ({v} {PVE} [amd64])\n"
+        out += "".join(l + "\n" for l in self.extra_sim)
+        return 0, out, ""
+
+
+def kfake(**kw):
+    f = KFake()
+    for k, v in kw.items():
+        setattr(f, k, v)
+    return f
+
+
+def kmode(f, mode, **extra):
+    f.plan = {"release_id": "kernel-t1", "layer": "kernel", "lane": "slow", "vmid": 9201, "mode": mode, "packages": []}
+    f.plan.update(extra)
+    return run(f)
+
+
+def staged(f=None):
+    f = f or kfake()
+    rc, rep = run(f)
+    assert rc == 0, rep
+    return f
+
+
+class KernelLane(unittest.TestCase):
+    """R-836 / `09` §3 decision 172: stage a kernel once through the ESP flag; the default moves only after a healthy
+    one-shot boot. Red-proof: audits/kernel-lane-2026-10-07/A/redproof.txt."""
+
+    def refused(self, f, code, mode=None, **extra):
+        rc, rep = kmode(f, mode, **extra) if mode else run(f)
+        self.assertEqual(rc, 2, rep)
+        self.assertEqual(rep["refused"]["code"], code, rep)
+        return rep
+
+    # --- the four red tests the brief names (Part A 3) ---
+    def test_installing_a_kernel_does_not_change_the_grub_default(self):
+        f = kfake()
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertIn(NEW, f.boot, "the new kernel was installed")
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD,
+                         "the default must stay the kernel the box runs (R-836: an install made the new one default)")
+        self.assertIn(f"gnulinux-{OLD}-advanced-{U}", f.tree[osapply.KERNEL_DEFAULT_CFG])
+        self.assertEqual(f.env, {"felhom_next": NEW}, "the ONLY way to the new kernel is the one-shot flag")
+        self.assertEqual(f.reboots, [], "staging never reboots")
+        st = json.loads(f.tree[osapply.KERNEL_STATE])
+        self.assertEqual((st["phase"], st["from"], st["to"]), ("staged", OLD, NEW))
+        self.assertEqual(rep["kernel"]["default"], OLD)
+
+    def test_a_box_without_the_esp_flag_is_refused(self):
+        for attr, val, frag in (("esp_fs", "ext4", "vfat"), ("efi", False, "UEFI"), ("snippets", False, "bundle"),
+                                ("mods", False, "module"), ("boot_mount", "/boot", "separate"), ("pin", True, "pinned")):
+            f = kfake(**{attr: val})
+            rep = self.refused(f, "R20")
+            self.assertIn(frag, rep["refused"]["reason"], attr)
+            self.assertNotIn(NEW, f.boot, f"{attr}: nothing may be installed on a refusal")
+            self.assertIsNone(f.env, f"{attr}: no flag on a refusal")
+
+    def test_a_reboot_without_the_flag_is_refused(self):
+        f = staged()
+        f.env = {"felhom_next": ""}
+        self.refused(f, "R22", mode="kernel-reboot")
+        self.assertEqual(f.reboots, [])
+
+    def test_a_kernel_outside_the_approved_set_is_refused(self):
+        # a signed set that names only the meta-package: the image the sources pull in was never signed for
+        f = kfake()
+        f.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        f.plan.update(select="listed", packages=[dict(KERNEL_SET[0])],
+                      signed=signed_job(packages=[KERNEL_SET[0]], op="os_kernel_step"))
+        self.refused(f, "R23")
+        self.assertNotIn(NEW, f.boot)
+        # a signed set names 7.0.14-22; the sources would ALSO bring 7.0.14-23
+        f2 = kfake()
+        f2.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        f2.plan.update(select="listed", packages=[dict(p) for p in KERNEL_SET],
+                       signed=signed_job(packages=KERNEL_SET, op="os_kernel_step"))
+        f2.extra_sim = ["Inst proxmox-kernel-7.0.14-23-pve-signed (7.0.14-23 Proxmox Debian Repository:stable [amd64])"]
+        self.refused(f2, "R23")
+        # a name that is not a kernel package at all
+        g = kfake()
+        g.plan.update(select="listed", packages=[{"name": "pve-manager", "version": "9.2.22", "origin": "Proxmox Debian Repository"}])
+        self.refused(g, "R23")
+        # the household was told about another kernel
+        h = kfake()
+        h.plan["expect_kver"] = "7.0.14-23-pve"
+        self.refused(h, "R23")
+        self.assertNotIn(NEW, h.boot)
+
+    def test_the_snippet_clears_the_flag_on_use(self):
+        """01_felhom_oneshot: the flag is copied, CLEARED and SAVED before any `set default`, all inside the one branch
+        that runs only when the flag is set; a default is set only for an installed kernel's own entry."""
+        text = (HERE / "felhom-grub-oneshot.sh").read_text()
+        body = text[text.index("cat <<EOF"):]
+        i_copy = body.index('set felhom_boot="\\${felhom_next}"')
+        i_clear = body.index("set felhom_next=\n")
+        i_save = body.index("save_env -f (\\$felhom_esp)/EFI/felhom/oneshot.env felhom_next")
+        i_default = body.index('set default="felhom-oneshot-%s"')
+        self.assertLess(i_copy, i_clear)
+        self.assertLess(i_clear, i_save)
+        self.assertLess(i_save, i_default, "the flag must be cleared on disk BEFORE GRUB boots anything")
+        self.assertIn('if [ "${felhom_boot}" = "%s" ]', body, "a default only for a kernel that is installed")
+        self.assertIn(osapply.ONESHOT_ENV[len(osapply.ESP_MOUNT):], text, "the wrapper and GRUB name the same env file")
+
+    # --- the rest of the stage ---
+    def test_option_c_options_are_on_the_one_shot_entry_only(self):
+        text = (HERE / "felhom-grub-oneshot-entries.sh").read_text()
+        self.assertIn(osapply.ONESHOT_ARGS, text)
+        self.assertIn("--id felhom-oneshot-$k", text)
+        self.assertNotIn("set default", text, "the entries file never sets the default")
+
+    def test_both_generators_ride_the_bundle(self):
+        self.assertEqual(osapply.BUNDLE_DESTS[osapply.ONESHOT_SNIPPET][1:4], ("felhom-grub-oneshot.sh", 0o755, "sh"))
+        self.assertEqual(osapply.BUNDLE_DESTS[osapply.ONESHOT_ENTRIES][1:4], ("felhom-grub-oneshot-entries.sh", 0o755, "sh"))
+
+    def test_ring0_pending_kernel_takes_only_the_kernel_set(self):
+        f = kfake()
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["authority"], "ring0")
+        self.assertEqual(sorted(u["name"] for u in rep["upgraded"]), ["proxmox-kernel-7.0", "pve-firmware"])
+        self.assertEqual(f.installed["pve-manager"], "9.2.21", "a Proxmox userspace package is the pve lane's")
+        self.assertEqual(f.installed["libc6"], "2.41-12+deb13u3", "a Debian package is the fast lane's")
+
+    def test_signed_listed_set_is_installed(self):
+        f = kfake()
+        f.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        f.plan.update(select="listed", packages=[dict(p) for p in KERNEL_SET],
+                      signed=signed_job(packages=KERNEL_SET, op="os_kernel_step"))
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["authority"], "signed")
+        self.assertEqual(f.env, {"felhom_next": NEW})
+
+    def test_no_authority_and_the_wrong_op_are_refused(self):
+        f = kfake()
+        f.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        self.refused(f, "R3")
+        g = kfake()
+        g.files[osapply.TRUST_FILE] = json.dumps({"host_id": "demo-hp-bb76ea", "ring0_slow_lane": False})
+        g.plan.update(select="listed", packages=[dict(p) for p in KERNEL_SET],
+                      signed=signed_job(packages=KERNEL_SET, op="os_pve_step"))
+        self.refused(g, "R3")
+
+    def test_fast_lane_byo_and_wrong_select_are_refused(self):
+        f = kfake()
+        f.plan["lane"] = "fast"
+        self.refused(f, "R3")
+        g = kfake()
+        g.files[osapply.INSTALL_STATE] = json.dumps({"mode": "byo"})
+        self.refused(g, "R12")
+        h = kfake()
+        h.plan["select"] = "pending-pve"
+        self.refused(h, "R11")
+        k = kfake()
+        k.plan.update(layer="host", lane="fast", mode="kernel-status")
+        self.refused(k, "R11")
+
+    def test_the_crash_guard_must_be_armed_and_quiet(self):
+        f = kfake()
+        f.files[osapply.CRASH_GUARD_STATE] = json.dumps({"armed": False, "tripped": True, "unclean_boots_in_window": 2})
+        self.refused(f, "R21")
+        g = kfake()
+        g.files[osapply.CRASH_GUARD_STATE] = json.dumps({"armed": True, "tripped": False, "unclean_boots_in_window": 1})
+        self.refused(g, "R21")
+        h = kfake()
+        del h.files[osapply.CRASH_GUARD_STATE]
+        self.refused(h, "R21")
+        self.assertNotIn(NEW, h.boot)
+
+    def test_never_two_steps_in_one_night(self):
+        f = staged()
+        self.refused(f, "R22")  # still staged
+        g = staged()
+        st = json.loads(g.tree[osapply.KERNEL_STATE])
+        st["phase"] = "good"
+        g.tree[osapply.KERNEL_STATE] = json.dumps(st)
+        g.clock += 3600
+        self.refused(g, "R22")  # done, but within 20 h
+
+    def test_removal_new_non_kernel_two_kernels_and_older_are_refused(self):
+        f = kfake(extra_sim=["Remv pve-firmware [3.18-3]"])
+        self.refused(f, "R4")
+        g = kfake(extra_sim=["Inst proxmox-new-thing (1.0 Proxmox Debian Repository:stable [all])"])
+        self.refused(g, "R6")
+        h = kfake(extra_sim=["Inst proxmox-kernel-7.0.14-23-pve-signed (7.0.14-23 Proxmox Debian Repository:stable [amd64])"])
+        self.refused(h, "R23")
+        k = kfake(running="7.0.14-23-pve")
+        k.boot = {"7.0.14-23-pve"}
+        k.cfg = k.render()
+        self.refused(k, "R23")
+        m = kfake()
+        m.origins = {"proxmox-kernel-7.0": DEB}
+        self.refused(m, "R2")
+
+    # R-898: ring 0 stages EXACTLY the told kernel (select listed, the set derived from it) — even when the sources
+    # offer a newer one by night; a told version that can no longer be installed is refused BEFORE any change (R7).
+    def test_ring0_listed_installs_the_told_kernel_not_the_newest(self):
+        f = kfake()
+        f.live["proxmox-kernel-7.0"] = {"7.0.14-20", "7.0.14-22", "7.0.2-6"}
+        f.live["proxmox-kernel-7.0.14-20-pve-signed"] = {"7.0.14-20"}
+        told = [{"name": "proxmox-kernel-7.0", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"},
+                {"name": "proxmox-kernel-7.0.14-20-pve-signed", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"}]
+        f.plan.update(select="listed", packages=told, expect_kver="7.0.14-20-pve")
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["authority"], "ring0")
+        self.assertEqual(f.env, {"felhom_next": "7.0.14-20-pve"})
+        self.assertEqual(f.installed["proxmox-kernel-7.0"], "7.0.14-20")
+        self.assertNotIn("7.0.14-22-pve", f.boot)
+
+    def test_ring0_told_kernel_gone_is_refused_before_any_change(self):
+        f = kfake()
+        f.live["proxmox-kernel-7.0"] = {"7.0.14-22"}   # 7.0.14-20 is no longer in the archive
+        told = [{"name": "proxmox-kernel-7.0", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"},
+                {"name": "proxmox-kernel-7.0.14-20-pve-signed", "version": "7.0.14-20", "origin": "Proxmox Debian Repository"}]
+        f.plan.update(select="listed", packages=told, expect_kver="7.0.14-20-pve")
+        rep = self.refused(f, "R7")
+        self.assertIsNone(f.env)
+        self.assertNotIn(osapply.KERNEL_DEFAULT_CFG, f.tree, "refused before the default was even pinned")
+        self.assertEqual(f.installed["proxmox-kernel-7.0"], "7.0.2-6")
+
+    def test_nothing_pending_changes_nothing(self):
+        f = kfake(kernel_pending=[])
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(rep["upgraded"], [])
+        self.assertIsNone(f.env)
+        self.assertNotIn(osapply.KERNEL_STATE, f.tree)
+
+    def test_a_failed_install_writes_no_flag(self):
+        f = kfake(install_rc=100)
+        rc, rep = run(f)
+        self.assertEqual(rc, 3, rep)
+        self.assertIsNone(f.env)
+        self.assertNotIn(osapply.KERNEL_STATE, f.tree)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD)
+
+    def test_a_postinst_without_update_grub_is_regenerated_and_proved(self):
+        f = kfake(grub_runs_in_postinst=False)
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        self.assertIn(f"felhom-oneshot-{NEW}", f.cfg)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD)
+
+    # --- the reboot, the boot, good / revert ---
+    def test_reboot_of_a_staged_step(self):
+        f = staged()
+        rc, rep = kmode(f, "kernel-reboot")
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(f.reboots, [OLD])
+        st = json.loads(f.tree[osapply.KERNEL_STATE])
+        self.assertEqual(st["phase"], "oneshot")
+        self.assertIn("host_services", st["health_before"])
+
+    def test_reboot_needs_a_staged_step(self):
+        self.refused(kfake(), "R22", mode="kernel-reboot")
+
+    def boot_into(self, f, kver):
+        f.running = kver
+        if f.env and f.env.get("felhom_next"):
+            f.env["felhom_next"] = ""   # GRUB cleared it (01_felhom_oneshot)
+        return kmode(f, "kernel-boot")
+
+    def test_healthy_one_shot_becomes_the_default(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        rc, rep = self.boot_into(f, NEW)
+        self.assertEqual((rc, rep["kernel_event"], rep["kernel"]["phase"]), (0, "judging", "judging"), rep)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD, "judging does not move the default")
+        rc, rep = kmode(f, "kernel-good")
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), NEW)
+        self.assertEqual(rep["kernel"]["phase"], "good")
+
+    def test_a_panic_falls_back_and_is_recorded(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        rc, rep = self.boot_into(f, OLD)
+        self.assertEqual((rc, rep["kernel_event"]), (0, "fell_back"), rep)
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD)
+        self.refused(f, "R22", mode="kernel-good")
+
+    def test_one_self_revert_then_never_again(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        self.boot_into(f, NEW)
+        rc, rep = kmode(f, "kernel-revert", reason="the customer guest is not running")
+        self.assertEqual(rc, 0, rep)
+        self.assertEqual(f.reboots, [OLD, NEW])
+        self.assertEqual(osapply.Kernel.default_kver(f.cfg), OLD, "the self-revert boots the default, the old kernel")
+        rc, rep = self.boot_into(f, OLD)
+        self.assertEqual(rep["kernel_event"], "self_reverted")
+        # the same step can never revert again
+        st = json.loads(f.tree[osapply.KERNEL_STATE])
+        st["phase"] = "judging"
+        f.tree[osapply.KERNEL_STATE] = json.dumps(st)
+        f.running = NEW
+        self.refused(f, "R22", mode="kernel-revert")
+        self.assertEqual(len(f.reboots), 2)
+
+    def test_a_revert_that_comes_back_new_is_never_retried(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        self.boot_into(f, NEW)
+        kmode(f, "kernel-revert")
+        rc, rep = self.boot_into(f, NEW)
+        self.assertEqual(rep["kernel_event"], "revert_failed")
+        self.refused(f, "R22", mode="kernel-revert")
+
+    def test_revert_refuses_an_unknown_default(self):
+        f = staged()
+        kmode(f, "kernel-reboot")
+        self.boot_into(f, NEW)
+        f.tree[osapply.KERNEL_DEFAULT_CFG] = f'GRUB_DEFAULT="gnulinux-advanced-{U}>gnulinux-9.9.9-1-pve-advanced-{U}"\n'
+        f.cfg = f.render()
+        self.refused(f, "R20", mode="kernel-revert")
+        self.assertEqual(len(f.reboots), 1)
+
+    def test_cancel_clears_the_flag(self):
+        f = staged()
+        rc, rep = kmode(f, "kernel-cancel")
+        self.assertEqual(rc, 0, rep)
+        self.assertFalse(f.env.get("felhom_next"), "the flag is gone")
+        self.assertEqual(rep["kernel"]["phase"], "cancelled")
+
+    def test_status_is_read_only_and_names_setup_problems(self):
+        f = kfake(esp_fs="ext4")
+        rc, rep = kmode(f, "kernel-status")
+        self.assertEqual(rc, 0, rep)
+        self.assertTrue(rep["kernel"]["setup_problems"])
+        self.assertEqual(f.tree, {})
+        self.assertFalse([c for c in f.calls if c[1][0] in ("update-grub", "systemctl", "apt-get")])
+
+    def test_facts_carry_the_kernel_lane(self):
+        f = staged()
+        f.plan = {"release_id": "facts", "layer": "host", "lane": "fast", "vmid": 9201, "mode": "facts", "packages": []}
+        rc, rep = run(f)
+        self.assertEqual(rc, 0, rep)
+        h = rep["facts"]["host"]
+        self.assertEqual(h["kernel_lane"]["phase"], "staged")
+        self.assertEqual(h["kernel_next_boot"], NEW)
+        self.assertIn("one-shot", h["kernel_next_boot_source"])
+
+
 if __name__ == "__main__":
     unittest.main()

configs/test_felhom_priv_apply.py

@@ -56,6 +56,18 @@ class FakeHost:
     def log(self, line):
         self.logs.append(line)
 
+    # controller-image (R-861 (a) A1): the ref arrives on stdin and is written INSIDE the guest by root.
+    stdin = b""
+    guest_writes = None
+
+    def read_stdin(self, limit):
+        return self.stdin[:limit + 1]
+
+    def write_guest_image(self, vmid, data):
+        if self.guest_writes is None:
+            self.guest_writes = []
+        self.guest_writes.append((vmid, data))
+
 
 LOCAL_UNIT = """# Managed by felhom-agent — do not edit by hand.
 [Unit]
@@ -316,5 +328,53 @@ class Refuses(unittest.TestCase):
         self.refused(h, ["wg", "/etc/shadow"], "A1")
 
 
+class ControllerImage(unittest.TestCase):
+    """R-861 (a) A1 (`09` §3 decision 165): the agent can no longer `tee` any image ref into the guest. The root verb
+    reads the ref on stdin, requires our registry + our repository + an x.y.z tag, and writes the guest file itself.
+    RED-PROOF: on the pre-A1 wrapper `controller-image` is not a verb (A1 usage, rc 2) — the accepted case fails."""
+
+    def go(self, ref, *argv):
+        h = FakeHost()
+        h.stdin = ref.encode() if isinstance(ref, str) else ref
+        return h, run(h, *(argv or ("controller-image", "9201")))
+
+    def test_our_controller_ref_is_written_in_the_guest(self):
+        h, rc = self.go("gitea.dooplex.hu/admin/felhom-controller:0.301.0\n")
+        self.assertEqual(rc, 0, h.logs)
+        self.assertEqual(h.guest_writes, [(9201, b"gitea.dooplex.hu/admin/felhom-controller:0.301.0\n")])
+
+    def test_a_foreign_image_is_refused(self):
+        for ref in ("docker.io/library/alpine:latest\n", "alpine\n",
+                    "gitea.dooplex.hu/admin/felhom-controller:latest\n",
+                    "gitea.dooplex.hu/admin/other:0.1.0\n",
+                    "evil.example/admin/felhom-controller:0.301.0\n",
+                    "gitea.dooplex.hu/admin/felhom-controller:0.301.0\nalpine\n",
+                    "gitea.dooplex.hu/admin/felhom-controller:0.301.0 x\n",
+                    "", "\n"):
+            h, rc = self.go(ref)
+            self.assertEqual(rc, 3, f"{ref!r} was accepted")
+            self.assertFalse(h.guest_writes, f"{ref!r} wrote the guest file")
+            self.assertTrue(any("[I1]" in l for l in h.logs), h.logs)
+
+    def test_oversize_stdin_is_refused(self):
+        h, rc = self.go("gitea.dooplex.hu/admin/felhom-controller:0.301.0" + " " * 300)
+        self.assertEqual(rc, 3)
+        self.assertFalse(h.guest_writes)
+
+    def test_vmid_must_be_numeric(self):
+        for argv in (("controller-image", "9201;id"), ("controller-image", "-1"), ("controller-image",),
+                     ("controller-image", "9201", "9202")):
+            h, rc = self.go("gitea.dooplex.hu/admin/felhom-controller:0.301.0\n", *argv)
+            self.assertIn(rc, (2, 3), argv)
+            self.assertFalse(h.guest_writes, argv)
+
+    def test_self_check_names_the_verb(self):
+        import io, contextlib
+        buf = io.StringIO()
+        with contextlib.redirect_stdout(buf):
+            pa.main(["--self-check"])
+        self.assertIn("controller-image", buf.getvalue())
+
+
 if __name__ == "__main__":
     unittest.main(verbosity=2)

internal/backup/backup_state.go

@@ -103,6 +103,29 @@ func (s *BackupSuccessState) LastKnownSuccess(target string, vmid int) (time.Tim
 	return e.at, ok
 }
 
+// KnownBackupSuccesses returns every saved success as a host-report record (the collector's
+// KnownBackupReporter, so the hub keeps its evidence across a restart). Only the tier, guest and start
+// time are known; the archive name is not saved and stays empty. Sorted for a stable report.
+func (s *BackupSuccessState) KnownBackupSuccesses() []hub.Backup {
+	if s == nil {
+		return nil
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	out := make([]hub.Backup, 0, len(s.last))
+	for _, e := range s.last {
+		out = append(out, hub.Backup{TargetID: e.target, VMID: e.vmid, Success: true, CrashConsistent: true,
+			StartedAt: e.at.Format(time.RFC3339), UncoveredVolumes: []string{}})
+	}
+	sort.Slice(out, func(i, j int) bool {
+		if out[i].TargetID != out[j].TargetID {
+			return out[i].TargetID < out[j].TargetID
+		}
+		return out[i].VMID < out[j].VMID
+	})
+	return out
+}
+
 func (s *BackupSuccessState) saveLocked() error {
 	entries := make([]backupSuccessJSON, 0, len(s.last))
 	for _, e := range s.last {

internal/backup/backup_state_test.go

@@ -57,3 +57,20 @@ func TestBackupSuccessState_CorruptFileIsEmpty(t *testing.T) {
 		t.Fatal("a corrupt file must read as nothing known")
 	}
 }
+
+// The saved successes come back as host-report records: success, tier, guest, start time (R-894 → the
+// host report, 2026-10-09). A new state read from the same file gives the same records (the restart case).
+func TestBackupSuccessState_KnownBackupSuccessesSurviveAReopen(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "backup-success-state.json")
+	s := NewBackupSuccessState(path)
+	if err := s.RecordBackupSuccess("felhom-backup", hub.Backup{VMID: 9201, Success: true, StartedAt: "2026-10-09T02:40:16Z"}); err != nil {
+		t.Fatal(err)
+	}
+	got := NewBackupSuccessState(path).KnownBackupSuccesses()
+	if len(got) != 1 || !got[0].Success || got[0].TargetID != "felhom-backup" || got[0].VMID != 9201 || got[0].StartedAt != "2026-10-09T02:40:16Z" {
+		t.Fatalf("got %+v", got)
+	}
+	if got[0].UncoveredVolumes == nil {
+		t.Fatal("uncovered_volumes must marshal as [], not null")
+	}
+}

internal/backup/foreign_key_ledger.go

@@ -0,0 +1,60 @@
+package backup
+
+import (
+	"context"
+	"sort"
+	"sync"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+)
+
+// ForeignKeyLedger (R-366 slice 2, `09` §3 decision 168) holds, per backup tier, the whole-guest archives the
+// restore-test pick skipped because another key wrote them (R-727 — an earlier install of this box). Since R-727 the
+// skip was one INFO log line per archive and nothing else, so after a reinstall the operator was never told that the
+// box's older whole-guest copies are unreadable to it. The host report carries this ledger; the hub raises ONE
+// operator event when it changes.
+//
+// It reports nil until a tier has been evaluated since the agent started, so a restart does not read as "the set
+// changed to empty" (the hub keeps its last state for an absent field).
+type ForeignKeyLedger struct {
+	mu       sync.Mutex
+	byTarget map[string]hub.ForeignKeyArchives
+}
+
+// NewForeignKeyLedger builds an empty ledger.
+func NewForeignKeyLedger() *ForeignKeyLedger {
+	return &ForeignKeyLedger{}
+}
+
+func (l *ForeignKeyLedger) set(target string, n int, oldest, newest int64) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.byTarget == nil {
+		l.byTarget = map[string]hub.ForeignKeyArchives{}
+	}
+	e := hub.ForeignKeyArchives{Target: target, Count: n}
+	if n > 0 {
+		e.Oldest = time.Unix(oldest, 0).UTC().Format(time.RFC3339)
+		e.Newest = time.Unix(newest, 0).UTC().Format(time.RFC3339)
+	}
+	l.byTarget[target] = e
+}
+
+// ForeignKeyArchives implements hub.ForeignKeyArchiveReporter: nil before any evaluation; otherwise the tiers that
+// hold such archives (`Tiers` empty, never nil, when none do), sorted by tier.
+func (l *ForeignKeyLedger) ForeignKeyArchives(context.Context) *hub.ForeignKeyArchivesStanza {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.byTarget == nil {
+		return nil
+	}
+	out := []hub.ForeignKeyArchives{}
+	for _, e := range l.byTarget {
+		if e.Count > 0 {
+			out = append(out, e)
+		}
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Target < out[j].Target })
+	return &hub.ForeignKeyArchivesStanza{Tiers: out}
+}

internal/backup/r366_foreign_key_ledger_test.go

@@ -0,0 +1,69 @@
+package backup
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+)
+
+// R-366 slice 2 (`09` §3 decision 168) — the restore-test's skip of an archive written with another key stops being
+// silent: the pick records, per tier, how many it skipped and their time range, and the host report carries it.
+//
+// COMPANION RED-PROOF (observed): remove the `r.foreign.set(...)` call from PickSettledRestoreCandidateOn → this fails
+// with "after one evaluation the ledger must report felhom-pbs: 2 archives …; got []". Restored.
+func TestR366_PickRecordsArchivesWrittenWithAnotherKey(t *testing.T) {
+	api := &fakeBackupAPI{
+		storages: []proxmox.Storage{{Storage: "felhom-pbs", Type: "pbs", EncryptionKey: thisBoxKey}},
+		content: []proxmox.StorageContent{
+			{VolID: "felhom-pbs:backup/ct/9201/2026-09-16T17:27:32Z", Content: "backup", VMID: 9201, Size: 4774114206, CTime: 1789579652, Encrypted: earlierBox2},
+			{VolID: "felhom-pbs:backup/ct/9201/2026-09-16T21:59:54Z", Content: "backup", VMID: 9201, Size: 20811501236, CTime: 1789595994, Encrypted: earlierBox1},
+			{VolID: "felhom-pbs:backup/ct/9201/2026-09-29T19:37:07Z", Content: "backup", VMID: 9201, Size: 3490689830, CTime: 1790710627, Encrypted: thisBoxKey},
+		},
+	}
+	r := NewBackupRunner(api, "local", proxmox.ModeSnapshot, "", "keep-last=1", quiet())
+	l := NewForeignKeyLedger()
+	r.SetForeignKeyLedger(l)
+
+	if got := l.ForeignKeyArchives(context.Background()); got != nil {
+		t.Fatalf("before any evaluation the ledger must be nil (the hub keeps its state); got %v", got)
+	}
+	if _, _, err := r.PickSettledRestoreCandidateOn(context.Background(), "felhom-pbs", time.Time{}); err != nil {
+		t.Fatal(err)
+	}
+	st := l.ForeignKeyArchives(context.Background())
+	want := hub.ForeignKeyArchives{Target: "felhom-pbs", Count: 2, Oldest: "2026-09-16T17:27:32Z", Newest: "2026-09-16T21:59:54Z"}
+	var got []hub.ForeignKeyArchives
+	if st != nil {
+		got = st.Tiers
+	}
+	if len(got) != 1 || got[0] != want {
+		t.Fatalf("after one evaluation the ledger must report felhom-pbs: 2 archives 2026-09-16T17:27:32Z…21:59:54Z; got %v", got)
+	}
+}
+
+// Evaluated and none found → the stanza with `tiers: []`; not evaluated → no stanza at all. Never a null on the wire.
+func TestR366_EvaluatedWithNoneIsAnEmptyList(t *testing.T) {
+	api := &fakeBackupAPI{
+		storages: []proxmox.Storage{{Storage: "felhom-pbs", Type: "pbs", EncryptionKey: thisBoxKey}},
+		content:  []proxmox.StorageContent{{VolID: "felhom-pbs:backup/ct/9201/2026-09-29T19:37:07Z", Content: "backup", VMID: 9201, Size: 3490689830, CTime: 1790710627, Encrypted: thisBoxKey}},
+	}
+	r := NewBackupRunner(api, "local", proxmox.ModeSnapshot, "", "keep-last=1", quiet())
+	l := NewForeignKeyLedger()
+	r.SetForeignKeyLedger(l)
+	b, _ := json.Marshal(hub.HostReport{ForeignKeyArchives: l.ForeignKeyArchives(context.Background())})
+	if strings.Contains(string(b), "foreign_key_archives") {
+		t.Fatalf("not evaluated must omit the stanza; got %s", b)
+	}
+	if _, _, err := r.PickSettledRestoreCandidateOn(context.Background(), "felhom-pbs", time.Time{}); err != nil {
+		t.Fatal(err)
+	}
+	b, _ = json.Marshal(hub.HostReport{ForeignKeyArchives: l.ForeignKeyArchives(context.Background())})
+	if !strings.Contains(string(b), `"foreign_key_archives":{"tiers":[]}`) {
+		t.Fatalf("evaluated with none must report tiers: []; got %s", b)
+	}
+}

internal/backup/runner.go

@@ -66,8 +66,13 @@ type BackupRunner struct {
 	// due-check is served from the local-API handler goroutines.
 	rejectedMu sync.Mutex
 	rejected   map[string]struct{}
+	// foreign (R-366 slice 2) records, per tier, the archives the pick skipped as another key's. nil = not wired.
+	foreign *ForeignKeyLedger
 }
 
+// SetForeignKeyLedger wires the R-366 slice-2 ledger the host report reads.
+func (r *BackupRunner) SetForeignKeyLedger(l *ForeignKeyLedger) { r.foreign = l }
+
 // NewBackupRunner builds a runner. mode defaults to snapshot (works for a stopped guest and
 // for lvm-thin); the caller may pass ModeStop for storages without snapshot support. retention is the
 // per-run prune spec ("keep-last=N", or "" to never prune) — only the periodic local backup sets it.
@@ -370,6 +375,8 @@ func (r *BackupRunner) PickSettledRestoreCandidateOn(ctx context.Context, target
 	var best string
 	var bestCTime int64 = -1
 	known := map[int]bool{} // vmid → the guest exists on this node (asked once per vmid per pick)
+	var foreignN int        // R-366 slice 2: archives skipped as another key's, and their time range
+	var foreignMin, foreignMax int64
 	for _, e := range contents {
 		if e.Content != "backup" {
 			continue
@@ -384,6 +391,13 @@ func (r *BackupRunner) PickSettledRestoreCandidateOn(ctx context.Context, target
 		}
 		if ownKey != "" && !strings.EqualFold(e.Encrypted, ownKey) {
 			r.noteNotAGuestBackupOnce(e, fmt.Sprintf("written by another box (key %s, this box's key %s) — not this box's proof", shortFP(e.Encrypted), shortFP(ownKey)))
+			foreignN++
+			if foreignMin == 0 || e.CTime < foreignMin {
+				foreignMin = e.CTime
+			}
+			if e.CTime > foreignMax {
+				foreignMax = e.CTime
+			}
 			continue
 		}
 		// R-689 (v0.136.0): … OF A GUEST THAT STILL EXISTS here. Measured on demo-hp 2026-09-27 right after
@@ -420,6 +434,9 @@ func (r *BackupRunner) PickSettledRestoreCandidateOn(ctx context.Context, target
 			bestCTime, best = e.CTime, e.VolID
 		}
 	}
+	if r.foreign != nil {
+		r.foreign.set(target, foreignN, foreignMin, foreignMax)
+	}
 	if best == "" {
 		return "", time.Time{}, nil
 	}

internal/capability/manifest.go

@@ -145,7 +145,8 @@ var manifest = []Capability{
 	{"controllerswap-image-inspect", "controller-swap / managed auto-update", "/usr/sbin/pct", []string{"exec", "9201", "--", "docker", "image", "inspect", "gitea.dooplex.hu/admin/felhom-controller:0.0.0"}, true, ""},
 	{"controllerswap-inspect", "controller-swap / managed auto-update", "/usr/sbin/pct", []string{"exec", "9201", "--", "docker", "inspect", "-f", "{{.State.Running}}", "felhom-controller"}, true, ""},
 	{"controllerswap-restart", "controller-swap / managed auto-update", "/usr/sbin/pct", []string{"exec", "9201", "--", "systemctl", "restart", "felhom-controller-bootstrap.service"}, true, ""},
-	{"controllerswap-write", "controller-swap / managed auto-update", "/usr/sbin/pct", []string{"exec", "9201", "--", "tee", "/etc/felhom-controller-image"}, true, ""},
+	// R-861 (a) A1 (decision 165): the write goes through the ROOT verb that checks the ref; the agent has no `tee` grant.
+	{"controllerswap-write", "controller-swap / managed auto-update", "/usr/local/sbin/felhom-priv-apply", []string{"controller-image", "9201"}, true, ""},
 
 	// ---- Stale-lock recovery (FELHOM_STALELOCK, v0.49.0; Critical: a guest stuck behind a stale
 	// reboot-during-backup lock can't start → the customer box stays DOWN until this clears it) ----

internal/capability/manifest_test.go

@@ -200,7 +200,8 @@ func TestRedProof_DroppedGrantFailsCheck(t *testing.T) {
 }
 
 // TestRedProof_DroppedControllerSwapTeeFailsCheck is the companion red-proof for the v0.45.0
-// FELHOM_CONTROLLERSWAP grants: with the `tee /etc/felhom-controller-image` line removed, the
+// FELHOM_CONTROLLERSWAP grants: with the write grant removed (since R-861 (a) A1 the `felhom-priv-apply controller-image`
+// line; before it, an agent `tee /etc/felhom-controller-image`), the
 // controllerswap-write capability MUST be reported uncovered. Proves the build gate watches the new
 // swap write grant (so dropping it can't ship a non-root agent that silently can't auto-update).
 func TestRedProof_DroppedControllerSwapTeeFailsCheck(t *testing.T) {
@@ -210,7 +211,7 @@ func TestRedProof_DroppedControllerSwapTeeFailsCheck(t *testing.T) {
 	}
 	var kept []string
 	for _, ln := range strings.Split(string(data), "\n") {
-		if strings.Contains(ln, "tee /etc/felhom-controller-image") {
+		if strings.Contains(ln, "felhom-priv-apply ^controller-image") { // R-861 (a) A1: the write's grant
 			continue
 		}
 		kept = append(kept, ln)
@@ -229,7 +230,7 @@ func TestRedProof_DroppedControllerSwapTeeFailsCheck(t *testing.T) {
 	}
 	cmdline := write.Binary + " " + strings.Join(write.ReprArgs, " ")
 	if matchesAny(cmdline, entries) {
-		t.Errorf("red-proof FAILED: controllerswap-write still matches after dropping the tee grant")
+		t.Errorf("red-proof FAILED: controllerswap-write still matches after dropping its grant")
 	}
 	if full := parseSudoersEntries(t, string(data)); !matchesAny(cmdline, full) {
 		t.Errorf("controllerswap-write should be covered by the real sudoers")

internal/capability/r861_injection_test.go

@@ -49,6 +49,10 @@ var r861Injections = []string{
 	"/usr/local/sbin/felhom-priv-apply unit ../../etc/x.mount",
 	"/usr/local/sbin/felhom-priv-apply dnsmasq /etc/shadow felhom-x.conf",
 	"/usr/local/sbin/felhom-priv-apply wg /etc/shadow",
+	// R-861 (a) A1 (decision 165): the agent wrote ANY image ref into the guest by `tee` — now only the root verb may
+	"/usr/sbin/pct exec 9201 -- tee /etc/felhom-controller-image",
+	"/usr/local/sbin/felhom-priv-apply controller-image 9201 9202",
+	"/usr/local/sbin/felhom-priv-apply controller-image 9201;id",
 }
 
 func TestSudoersRefusesTheR861Injections(t *testing.T) {
@@ -93,3 +97,42 @@ func TestSudoersFstrimRuleIsExact(t *testing.T) {
 		}
 	}
 }
+
+// R-861 (a) A1: the managed controller update still has its route — the root verb, one numeric vmid.
+func TestSudoersAllowsTheControllerImageVerb(t *testing.T) {
+	data, err := os.ReadFile(sudoersPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !matchesAny("/usr/local/sbin/felhom-priv-apply controller-image 9201", parseSudoersEntries(t, string(data))) {
+		t.Fatal("the sudoers does not allow `felhom-priv-apply controller-image 9201` — a managed controller update cannot write its image")
+	}
+}
+
+// R-861 (b) B2 (decision 165, hygiene): felhom-op's `pct start|stop|unlock` grants are ONE numeric vmid each. The old
+// glob `[0-9]*` eats spaces, so `pct stop 9201 --skiplock 1` and two vmids matched.
+// RED-PROOF: on the pre-B2 felhom-op.sudoers (`/usr/sbin/pct stop [0-9]*`) the decoys match.
+func TestFelhomOpSudoersPctIsExact(t *testing.T) {
+	data, err := os.ReadFile("../../configs/felhom-op.sudoers")
+	if err != nil {
+		t.Fatal(err)
+	}
+	entries := parseSudoersEntries(t, string(data))
+	for _, ok := range []string{"/usr/sbin/pct start 9201", "/usr/sbin/pct stop 9201", "/usr/sbin/pct unlock 9201", "/usr/sbin/pct list"} {
+		if !matchesAny(ok, entries) {
+			t.Errorf("felhom-op lost a repair verb: %s", ok)
+		}
+	}
+	for _, bad := range []string{
+		"/usr/sbin/pct stop 9201 --skiplock 1",
+		"/usr/sbin/pct start 9201 9202",
+		"/usr/sbin/pct unlock 9201 --whatever",
+		"/usr/sbin/pct start 92a1",
+		"/usr/sbin/pct stop ",
+		"/usr/sbin/pct destroy 9201",
+	} {
+		if matchesAny(bad, entries) {
+			t.Errorf("felhom-op's sudoers allows %q", bad)
+		}
+	}
+}

internal/escrow/recover.go

@@ -59,8 +59,26 @@ var (
 	// It carries no material and no code: only WHICH earlier package opened, by its supersession date,
 	// which is the one fact the customer needs to recognise it.
 	ErrCodeOpensRetained = errors.New("escrow: the recovery code did not open the CURRENT sealed package, but it DID open a retained earlier one")
+	// ErrRetainedUnchecked — the code did NOT open the current package, and NOT every earlier package the hub
+	// holds for this host was tried (R-304, 2026-10-08): the retained list could not be fetched, the hub
+	// withheld rows (over its serve cap, or rows with no key material), a package was malformed, or the
+	// attempt cap stopped the loop. So „the code is wrong" is NOT known — it may be right for a package
+	// nobody tried. Distinct from a mistype for exactly the R-224 reason: never accuse the customer of
+	// something we did not check.
+	ErrRetainedUnchecked = errors.New("escrow: the recovery code did not open the current sealed package, and some earlier packages were NOT checked")
 )
 
+// RetainedUncheckedError wraps ErrRetainedUnchecked with how many earlier packages went unchecked
+// (-1 = unknown: the retained list itself could not be read). No secret.
+type RetainedUncheckedError struct {
+	Unchecked int
+}
+
+func (e *RetainedUncheckedError) Error() string {
+	return fmt.Sprintf("%s (unchecked=%d)", ErrRetainedUnchecked.Error(), e.Unchecked)
+}
+func (e *RetainedUncheckedError) Unwrap() error { return ErrRetainedUnchecked }
+
 // RetainedMatch says which retained package a code opened. Returned inside RetainedOpenedError; it
 // carries no secret — not the code, not the bundle, not the repository password.
 type RetainedMatch struct {
@@ -102,8 +120,10 @@ type RetainedBlob struct {
 }
 
 // RetainedFetcher yields this host's RETAINED sealed packages, newest-superseded first. An empty
-// slice is a clean "none". R-311.
+// slice is a clean "none". R-311. `withheld` counts the earlier packages the hub holds that are NOT in
-type RetainedFetcher func(ctx context.Context) (blobs []RetainedBlob, unopenable int, err error)
+// blobs — rows with no key material, rows over the hub's serve cap, and packages dropped as malformed
+// (R-304): each is a package the code was never tried against.
+type RetainedFetcher func(ctx context.Context) (blobs []RetainedBlob, withheld int, err error)
 
 // OffsiteKeyRecoverer is the assembled links 6→8. Construct it with a fetcher; call it with R.
 type OffsiteKeyRecoverer struct {
@@ -154,9 +174,14 @@ func (r OffsiteKeyRecoverer) RecoverOffsiteRepoPassword(ctx context.Context, rec
 		// from the unwrap alone; the only way to tell is to try. Until this existed nobody tried, and
 		// the screen said so out loud ("innen nem tudjuk megkülönböztetni őket") — a true sentence
 		// about our own incuriosity, read by the customer as a statement about their code.
-		if m, ok := r.tryRetained(ctx, recoveryCode); ok {
+		m, ok, unchecked := r.tryRetained(ctx, recoveryCode)
+		if ok {
 			return "", &RetainedOpenedError{Match: m}
 		}
+		// R-304: only when EVERY earlier package the hub holds was tried may this stay a wrong code.
+		if unchecked != 0 {
+			return "", &RetainedUncheckedError{Unchecked: unchecked}
+		}
 		return "", err // the fail-closed "the recovery code did not unwrap…" message; no secret in it
 	}
 	if bundle.ResticRepoPassword == "" {
@@ -173,23 +198,38 @@ func (r OffsiteKeyRecoverer) RecoverOffsiteRepoPassword(ctx context.Context, rec
 // function breaking is the behaviour we had before it existed.
 //
 // NOTHING IS LOGGED HERE and no return value carries the code, a bundle or a password.
-func (r OffsiteKeyRecoverer) tryRetained(ctx context.Context, recoveryCode string) (RetainedMatch, bool) {
+//
+// R-304 (2026-10-08): it also returns how many earlier packages were NOT tried — `withheld` from the hub, plus
+// the ones past the attempt cap — or -1 when the retained list could not be read at all. A nil FetchRetained
+// (an agent wired without the lookup) reports 0: the pre-R-311 refusal, unchanged.
+func (r OffsiteKeyRecoverer) tryRetained(ctx context.Context, recoveryCode string) (RetainedMatch, bool, int) {
 	if r.FetchRetained == nil {
-		return RetainedMatch{}, false
+		return RetainedMatch{}, false, 0
 	}
-	blobs, _, err := r.FetchRetained(ctx)
+	blobs, withheld, err := r.FetchRetained(ctx)
-	if err != nil || len(blobs) == 0 {
+	if err != nil {
-		return RetainedMatch{}, false
+		return RetainedMatch{}, false, -1
+	}
+	if withheld < 0 {
+		withheld = 0
+	}
+	if len(blobs) == 0 {
+		return RetainedMatch{}, false, withheld
 	}
 	limit := r.MaxRetainedTried
 	if limit <= 0 {
 		limit = defaultMaxRetainedTried
 	}
+	unchecked := withheld
+	if len(blobs) > limit {
+		unchecked += len(blobs) - limit
+	}
 	for i, rb := range blobs {
 		if i >= limit {
 			break
 		}
 		if len(rb.Blob) == 0 {
+			unchecked++
 			continue
 		}
 		bundle, uerr := UnwrapIdentityBundle(ctx, rb.Blob, recoveryCode)
@@ -204,7 +244,7 @@ func (r OffsiteKeyRecoverer) tryRetained(ctx context.Context, recoveryCode strin
 			// correct and must be told so — but the history behind it still cannot be reopened, and
 			// saying otherwise would be a promise this path cannot keep.
 			HasResticPassword: bundle.ResticRepoPassword != "",
-		}, true
+		}, true, 0
 	}
-	return RetainedMatch{}, false
+	return RetainedMatch{}, false, unchecked
 }

internal/escrow/recover_retained_test.go

@@ -115,8 +115,9 @@ func TestRecover_WrongCode_StaysAPlainRefusal(t *testing.T) {
 	}
 }
 
-// FAIL-SAFE — if the retained lookup itself fails, the original refusal must stand UNCHANGED. The
+// FAIL-SAFE — if the retained lookup itself fails, the lookup's error never reaches the customer and no
-// worst outcome of this feature breaking is the behaviour we had before it.
+// retained package is claimed. R-304 (2026-10-08) changed what stands instead: not the wrong-code refusal (the
+// earlier packages were never tried, so „wrong" is not known) but ErrRetainedUnchecked with Unchecked = -1.
 //
 // RED-PROOF: make tryRetained propagate the fetch error instead of returning false → the customer
 // gets a new, unexplained failure mode → this FAILS.
@@ -140,6 +141,10 @@ func TestRecover_RetainedFetchFails_OriginalRefusalStands(t *testing.T) {
 	if containsStr(err.Error(), "hub exploded") {
 		t.Error("the retained-lookup failure leaked into the customer-facing refusal — it must be silent")
 	}
+	var ue *RetainedUncheckedError
+	if !errors.As(err, &ue) || ue.Unchecked != -1 {
+		t.Errorf("err = %v, want RetainedUncheckedError{-1} — the earlier packages were never tried (R-304)", err)
+	}
 }
 
 // A nil FetchRetained keeps the pre-R-311 behaviour EXACTLY. An agent wired without it must be
@@ -228,3 +233,72 @@ func containsStr(hay, needle string) bool {
 		return false
 	})()
 }
+
+// ── R-304 (2026-10-08) — „wrong code" only when every earlier package was tried ──────────────────────
+//
+// The consequence asserted: is the refusal a WRONG CODE (the only error the screen may answer with „check your
+// typing")? It may be only when the hub withheld nothing and every served package was tried.
+//
+// RED-PROOF: make tryRetained return 0 for `unchecked` → the three „unchecked" cases return the plain refusal
+// → they FAIL; the all-tried case keeps passing.
+func TestR304_WrongCodeOnlyWhenEveryEarlierPackageWasTried(t *testing.T) {
+	ensureAge(t)
+	current := sealBundle(t, IdentityBundle{ResticRepoPassword: "4444567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef"}, testR)
+	other := sealBundle(t, IdentityBundle{ResticRepoPassword: "5555567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef"}, testR)
+	const code = "a code that opens nothing whatsoever in this test"
+	cases := []struct {
+		name      string
+		blobs     int
+		withheld  int
+		limit     int
+		unchecked int // 0 = must be a plain wrong code
+	}{
+		{"all tried, nothing withheld", 2, 0, 6, 0},
+		{"the hub withheld rows (no key material / over its cap)", 1, 3, 6, 3},
+		{"only withheld rows, nothing served", 0, 2, 6, 2},
+		{"the attempt cap stopped the loop", 5, 0, 2, 3},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			blobs := make([]RetainedBlob, 0, c.blobs)
+			for i := 0; i < c.blobs; i++ {
+				blobs = append(blobs, RetainedBlob{Blob: other, SupersededAt: "2026-08-01 00:00:00", Index: i})
+			}
+			_, err := OffsiteKeyRecoverer{
+				Fetch: fetcherFor(current),
+				FetchRetained: func(context.Context) ([]RetainedBlob, int, error) {
+					return blobs, c.withheld, nil
+				},
+				MaxRetainedTried: c.limit,
+			}.RecoverOffsiteRepoPassword(context.Background(), code)
+			if err == nil {
+				t.Fatal("a code that opens nothing succeeded")
+			}
+			var ue *RetainedUncheckedError
+			isUnchecked := errors.As(err, &ue)
+			if c.unchecked == 0 {
+				if isUnchecked {
+					t.Fatalf("every earlier package was tried — this IS a wrong code, got %v", err)
+				}
+				return
+			}
+			if !isUnchecked || ue.Unchecked != c.unchecked || !errors.Is(err, ErrRetainedUnchecked) {
+				t.Fatalf("err = %v, want RetainedUncheckedError{%d} — never call the code wrong when packages were not tried", err, c.unchecked)
+			}
+		})
+	}
+}
+
+// A malformed (empty) served package counts as not tried.
+func TestR304_EmptyServedPackageCountsAsUnchecked(t *testing.T) {
+	ensureAge(t)
+	current := sealBundle(t, IdentityBundle{ResticRepoPassword: "6666567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef"}, testR)
+	_, err := OffsiteKeyRecoverer{
+		Fetch:         fetcherFor(current),
+		FetchRetained: retainedFetcherFor(RetainedBlob{Blob: nil, SupersededAt: "2026-08-01 00:00:00"}),
+	}.RecoverOffsiteRepoPassword(context.Background(), testR2)
+	var ue *RetainedUncheckedError
+	if !errors.As(err, &ue) || ue.Unchecked != 1 {
+		t.Fatalf("err = %v, want RetainedUncheckedError{1}", err)
+	}
+}

internal/hub/collect.go

@@ -66,6 +66,13 @@ type ProvenRestoreTestReporter interface {
 	ProvenRestoreTests(ctx context.Context) []RestoreTest
 }
 
+// KnownBackupReporter is the newest SUCCESSFUL backup per tier and guest kept on disk (R-894's
+// backup-success-state.json). collectBackups folds it into the report so a restart does not erase the
+// hub's evidence of a backup that ran minutes before it (the kernel-night shape, 2026-10-09).
+type KnownBackupReporter interface {
+	KnownBackupSuccesses() []Backup
+}
+
 // PBSReporter is the slice-6-Phase-B seam the pbs verify loop plugs into (same pattern).
 // Returns the agent's latest-known PBS snapshot inventory + verify-state. nil → empty.
 type PBSReporter interface {
@@ -105,6 +112,7 @@ type Collector struct {
 	backups          BackupReporter
 	restoreTests     RestoreTestReporter
 	provenTests      ProvenRestoreTestReporter
+	knownBackups     KnownBackupReporter // R-894 file → host report after a restart (nil → in-memory only)
 	pbs              PBSReporter
 	temp             TempReader                                    // slice 9: host CPU/chassis temp (nil-safe → nil temp)
 	capProbe         func(ctx context.Context) []capability.Status // v0.44.0: privileged-capability self-check (nil → empty)
@@ -115,6 +123,7 @@ type Collector struct {
 	ctrlSup          ControllerSupervisorReporter                  // R-523: in-guest controller supervisor (nil → stanza omitted)
 	guestNet         GuestNetReporter                              // R-54: per-guest network watchdog (nil → stanza omitted)
 	diskTrim         GuestDiskTrimReporter                         // R-444: weekly guest disk trim (nil → stanza omitted)
+	foreignKey       ForeignKeyArchiveReporter                     // R-366 slice 2 (nil → omitted)
 	selfUpdate       SelfUpdateReporter                            // D1: agent self-update pending status (nil → false)
 	mgmtPlane        MgmtPlaneReporter                             // G1: management-plane health (nil → stanza omitted)
 	oob              OOBReporter                                   // H1: operator-access health (nil → stanza omitted)
@@ -228,6 +237,18 @@ func (c *Collector) SetGuestNetReporter(g GuestNetReporter) *Collector {
 	return c
 }
 
+// ForeignKeyArchiveReporter is the R-366 slice-2 seam: the restore-test's ledger of archives written with another
+// key. nil = not evaluated yet (the stanza is omitted and the hub keeps its state).
+type ForeignKeyArchiveReporter interface {
+	ForeignKeyArchives(ctx context.Context) *ForeignKeyArchivesStanza
+}
+
+// SetForeignKeyArchiveReporter wires the restore-test's foreign-key ledger (R-366 slice 2; nil-safe → omitted).
+func (c *Collector) SetForeignKeyArchiveReporter(r ForeignKeyArchiveReporter) *Collector {
+	c.foreignKey = r
+	return c
+}
+
 // SetGuestDiskTrimReporter wires the R-444 weekly trim job as a report source (nil-safe → stanza omitted).
 func (c *Collector) SetGuestDiskTrimReporter(r GuestDiskTrimReporter) *Collector {
 	c.diskTrim = r
@@ -394,6 +415,10 @@ func (c *Collector) Collect(ctx context.Context) (*HostReport, error) {
 	if c.diskTrim != nil {
 		report.GuestDiskTrim = c.diskTrim.GuestDiskTrimStatus(ctx)
 	}
+	// R-366 slice 2: archives the restore-test skipped as another key's (nil → not evaluated yet → omitted).
+	if c.foreignKey != nil {
+		report.ForeignKeyArchives = c.foreignKey.ForeignKeyArchives(ctx)
+	}
 	// D1: agent self-update pending status (nil reporter → pending=false, the steady state).
 	if c.selfUpdate != nil {
 		report.SelfUpdatePending, report.SelfUpdatePendingVersion = c.selfUpdate.SelfUpdatePending()
@@ -559,14 +584,50 @@ func (c *Collector) collectStorage(ctx context.Context) []StorageTarget {
 // collectBackups / collectRestoreTests read the agent's latest backup + restore-test state
 // via the seams. Best-effort: a nil reporter or nil slice degrades to an empty (non-nil)
 // list so the collection always marshals as [].
+//
+// The saved successes (SetKnownBackupReporter) are added for each tier and guest the in-memory list has
+// no success for at or after the saved time. Why: the in-memory list is empty after an agent restart,
+// and the hub's backup-freshness check reads only what the reports carried. Measured 2026-10-09 on
+// demo-felhom: the night backup landed 02:40 UTC, the kernel step restarted the host at 02:44, no report
+// fell in between, so two kernel nights in a row left no trace and the hub alarmed „newest backup is 48h
+// old" at 03:00. Only SUCCESSES are saved, so a failure is never hidden and never invented.
+// Pinned by TestCollectBackups_SavedSuccessSurvivesARestart.
 func (c *Collector) collectBackups(ctx context.Context) []Backup {
-	if c.backups == nil {
+	out := []Backup{}
-		return []Backup{}
+	if c.backups != nil {
+		if b := c.backups.Backups(ctx); b != nil {
+			out = append(out, b...)
+		}
 	}
-	if b := c.backups.Backups(ctx); b != nil {
+	if c.knownBackups == nil {
-		return b
+		return out
 	}
-	return []Backup{}
+	for _, k := range c.knownBackups.KnownBackupSuccesses() {
+		kt, err := time.Parse(time.RFC3339, k.StartedAt)
+		if err != nil {
+			continue
+		}
+		covered := false
+		for _, b := range out {
+			if !b.Success || b.TargetID != k.TargetID || b.VMID != k.VMID {
+				continue
+			}
+			if bt, err := time.Parse(time.RFC3339, b.StartedAt); err == nil && !bt.Before(kt) {
+				covered = true
+				break
+			}
+		}
+		if !covered {
+			out = append(out, k)
+		}
+	}
+	return out
+}
+
+// SetKnownBackupReporter wires the R-894 saved successes into the host report (nil-safe → in-memory only).
+func (c *Collector) SetKnownBackupReporter(r KnownBackupReporter) *Collector {
+	c.knownBackups = r
+	return c
 }
 
 // collectRestoreTests merges the in-memory result with the PERSISTED per-tier proofs (R-189).

internal/hub/collect_knownbackups_test.go

@@ -0,0 +1,62 @@
+package hub
+
+import (
+	"context"
+	"testing"
+)
+
+type fakeMemBackups []Backup
+
+func (f fakeMemBackups) Backups(context.Context) []Backup { return f }
+
+type fakeKnownBackups []Backup
+
+func (f fakeKnownBackups) KnownBackupSuccesses() []Backup { return f }
+
+// The consequence, not the mechanism: after a restart (empty in-memory list) the host report still carries
+// the night's backup, so the hub's freshness check sees it. Measured 2026-10-09 on demo-felhom: without this
+// the report carried backups: [] and the hub alarmed „newest backup is 48h old" an hour after a good backup.
+// RED-PROOF: return before the saved-success loop in collectBackups → the first case reports nothing → fails.
+func TestCollectBackups_SavedSuccessSurvivesARestart(t *testing.T) {
+	saved := Backup{TargetID: "felhom-backup", VMID: 9201, Success: true, StartedAt: "2026-10-09T02:40:16Z"}
+
+	t.Run("restart: memory empty, the saved success is reported", func(t *testing.T) {
+		c := &Collector{backups: fakeMemBackups(nil), knownBackups: fakeKnownBackups{saved}}
+		got := c.collectBackups(context.Background())
+		if len(got) != 1 || got[0].StartedAt != saved.StartedAt || !got[0].Success || got[0].TargetID != "felhom-backup" {
+			t.Fatalf("want the saved success, got %+v", got)
+		}
+	})
+
+	t.Run("memory holds the same or a newer success: no second entry", func(t *testing.T) {
+		mem := Backup{TargetID: "felhom-backup", VMID: 9201, Success: true, StartedAt: "2026-10-09T02:40:16Z", Archive: "a"}
+		c := &Collector{backups: fakeMemBackups{mem}, knownBackups: fakeKnownBackups{saved}}
+		if got := c.collectBackups(context.Background()); len(got) != 1 || got[0].Archive != "a" {
+			t.Fatalf("want only the in-memory record, got %+v", got)
+		}
+	})
+
+	t.Run("a newer FAILURE in memory never hides the saved success, and is kept", func(t *testing.T) {
+		fail := Backup{TargetID: "felhom-backup", VMID: 9201, Success: false, StartedAt: "2026-10-10T02:40:00Z", Error: "x"}
+		c := &Collector{backups: fakeMemBackups{fail}, knownBackups: fakeKnownBackups{saved}}
+		got := c.collectBackups(context.Background())
+		if len(got) != 2 || got[0].Success || !got[1].Success {
+			t.Fatalf("want the failure and the saved success, got %+v", got)
+		}
+	})
+
+	t.Run("another tier's success does not cover this tier", func(t *testing.T) {
+		other := Backup{TargetID: "felhom-pbs", VMID: 9201, Success: true, StartedAt: "2026-10-10T00:00:00Z"}
+		c := &Collector{backups: fakeMemBackups{other}, knownBackups: fakeKnownBackups{saved}}
+		if got := c.collectBackups(context.Background()); len(got) != 2 {
+			t.Fatalf("want both tiers, got %+v", got)
+		}
+	})
+
+	t.Run("no saved state wired: the in-memory list as before, never nil", func(t *testing.T) {
+		c := &Collector{}
+		if got := c.collectBackups(context.Background()); got == nil || len(got) != 0 {
+			t.Fatalf("want an empty non-nil list, got %#v", got)
+		}
+	})
+}

internal/hub/report.go

@@ -129,6 +129,12 @@ type HostReport struct {
 	// wired; an empty `guests` list means the job runs and no guest has been trimmed yet. No secret.
 	GuestDiskTrim *GuestDiskTrimStatus `json:"guest_disk_trim,omitempty"`
 
+	// ForeignKeyArchives (R-366 slice 2, `09` §3 decision 168): per backup tier, the whole-guest archives the
+	// restore-test SKIPPED because they were written with another key (an earlier install of this box). This box
+	// cannot open them; the hub turns a CHANGE of this list into one operator event. Absent = not evaluated yet since
+	// the agent started (the hub keeps its last state); `tiers: []` = evaluated, none found.
+	ForeignKeyArchives *ForeignKeyArchivesStanza `json:"foreign_key_archives,omitempty"`
+
 	// LogTail is the agent's on-demand debug-ring tail (v0.83.0 observability) — the agent
 	// mirror of the controller's report log_tails channel. Present ONLY on the heartbeat
 	// right after the control envelope requested it (log_tail_requested); consume-once on
@@ -630,6 +636,17 @@ type WireOSUpdate struct {
 	// HostRelease is the newest approved HOST release (hub v0.131.0, `11` §8 step 3) — a separate set: a version
 	// approved for the guest is not approved for the host by that fact alone.
 	HostRelease *WireOSRelease `json:"host_release,omitempty"`
+	// Kernel is the kernel lane's instruction for THIS box (R-836, `09` §3 decision 172, `11` §5.11): the kernel the
+	// household was told about, and whether tonight is a told night. Nil (an older hub, or no kernel due) = no kernel
+	// step. The hub sets Tonight only after the household's mail the day before went out — no mail, no step.
+	Kernel *WireKernelStep `json:"kernel,omitempty"`
+}
+
+// WireKernelStep is the hub's kernel-lane instruction (hub osupdates.KernelBlock — field-exact, cross-repo).
+type WireKernelStep struct {
+	Kver       string `json:"kver"`                  // e.g. "7.0.14-22-pve" — the wrapper refuses any other (R23)
+	Tonight    bool   `json:"tonight"`               // the household was mailed the day before: tonight's leg may reboot
+	NotifiedAt string `json:"notified_at,omitempty"` // when that mail went out (RFC 3339), for the log
 }
 
 // WireOSRelease is an approved version set; Snapshot is the approval time (YYYYMMDDTHHMMSSZ) the wrapper uses
@@ -726,3 +743,18 @@ type WireRestoreDirective struct {
 	Archive string `json:"archive,omitempty"` // source archive/snapshot to restore from
 	VMID    int    `json:"vmid,omitempty"`
 }
+
+// ForeignKeyArchivesStanza wraps the per-tier list so "evaluated, none" (`tiers: []`) differs from "not evaluated"
+// (the stanza absent) without a null on the wire.
+type ForeignKeyArchivesStanza struct {
+	Tiers []ForeignKeyArchives `json:"tiers"`
+}
+
+// ForeignKeyArchives is one tier's count of archives written with another key (R-366 slice 2): the count and the
+// newest/oldest archive time (RFC3339, UTC). No key material — the fingerprints stay on the box.
+type ForeignKeyArchives struct {
+	Target string `json:"target"`
+	Count  int    `json:"count"`
+	Oldest string `json:"oldest"`
+	Newest string `json:"newest"`
+}

internal/localapi/afterbackup_test.go

@@ -15,7 +15,7 @@ import (
 // Red-proof: drop the `b.Success &&` guard and the failed-backup sub-case fails; move the call after release()
 // and the gate sub-case fails.
 func TestAfterPrimaryBackup(t *testing.T) {
-	run := func(t *testing.T, failErr string) (calls []int, gateHeld bool) {
+	run := func(t *testing.T, failErr, path string) (calls []int, gateHeld bool) {
 		gate := &backup.InFlight{}
 		b := &fakeBackups{failErr: failErr}
 		srv := newTestServerS(t, &fakeGuests{}, b, &fakeStore{}, nil)
@@ -34,7 +34,7 @@ func TestAfterPrimaryBackup(t *testing.T) {
 			done <- struct{}{}
 		})
 		h := srv.Handler()
-		if do(t, h, "POST", "/backup", "A", "").Code != http.StatusAccepted {
+		if do(t, h, "POST", path, "A", "").Code != http.StatusAccepted {
 			t.Fatal("POST /backup not accepted")
 		}
 		select {
@@ -47,7 +47,7 @@ func TestAfterPrimaryBackup(t *testing.T) {
 		return calls, gateHeld
 	}
 	t.Run("success runs the leg under the gate", func(t *testing.T) {
-		calls, held := run(t, "")
+		calls, held := run(t, "", "/backup")
 		if len(calls) != 1 {
 			t.Fatalf("the leg ran %d time(s), want 1", len(calls))
 		}
@@ -56,8 +56,21 @@ func TestAfterPrimaryBackup(t *testing.T) {
 		}
 	})
 	t.Run("a failed backup runs nothing", func(t *testing.T) {
-		if calls, _ := run(t, "vzdump exploded"); len(calls) != 0 {
+		if calls, _ := run(t, "vzdump exploded", "/backup"); len(calls) != 0 {
 			t.Fatalf("the leg ran after a FAILED backup: %v", calls)
 		}
 	})
+	// R-899: a household press is not the night's backup — no OS leg after it. Same fake, same successful backup as
+	// the first sub-case; only the query differs. Red-proof: make handleBackup ignore `trigger` and this sub-case
+	// fails with the leg run once.
+	t.Run("a manual press runs nothing", func(t *testing.T) {
+		if calls, _ := run(t, "", "/backup?trigger=manual"); len(calls) != 0 {
+			t.Fatalf("the OS leg ran after a manual press: %v", calls)
+		}
+	})
+	t.Run("the scheduled path with the new query still runs the leg", func(t *testing.T) {
+		if calls, _ := run(t, "", "/backup?trigger=night"); len(calls) != 1 {
+			t.Fatalf("the leg ran %d time(s) after a non-manual backup, want 1", len(calls))
+		}
+	})
 }

internal/localapi/controllersupervisor_test.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
-	"io"
 	"log/slog"
 	"os"
 	"path/filepath"
@@ -54,8 +53,8 @@ func (f *supExec) GuestExec(_ context.Context, vmid int, args ...string) (string
 	}
 	return "", errors.New("supExec: unexpected args")
 }
-func (f *supExec) GuestExecStdin(context.Context, int, io.Reader, ...string) (string, error) {
+func (f *supExec) WriteControllerImage(context.Context, int, string) error {
-	return "", errors.New("supExec: no stdin exec expected")
+	return errors.New("supExec: no image write expected")
 }
 func (f *supExec) count(vmid int) int {
 	f.mu.Lock()

internal/localapi/controllerswap.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io"
 	"log/slog"
 	"net/http"
 	"os"
@@ -41,9 +40,10 @@ func ValidControllerImage(ref string) bool { return controllerImageRe.MatchStrin
 // faked in tests. The single seam the swap composes over (no hand-rolled pct).
 type GuestExecutor interface {
 	GuestExec(ctx context.Context, vmid int, args ...string) (string, error)
-	// GuestExecStdin is GuestExec with the command's stdin fed from stdin — the swap write pipes the
+	// WriteControllerImage writes the image ref into the guest's /etc/felhom-controller-image through the ROOT
-	// image ref into an in-guest `tee` (no shell vector).
+	// verb `felhom-priv-apply controller-image <vmid>` (R-861 (a) A1, `09` §3 decision 165), which re-checks the
-	GuestExecStdin(ctx context.Context, vmid int, stdin io.Reader, args ...string) (string, error)
+	// ref against our registry + repository + x.y.z. The agent no longer holds a `tee` grant into the guest.
+	WriteControllerImage(ctx context.Context, vmid int, image string) error
 }
 
 // ControllerSwapState is the durable record of a swap (crash-safety + status). Written before the swap
@@ -141,14 +141,11 @@ func (c *ControllerSwapper) imagePresent(ctx context.Context, vmid int, image st
 }
 
 func (c *ControllerSwapper) writeImage(ctx context.Context, vmid int, image string) error {
-	// Non-root path: pipe the image ref into an in-guest `tee` over stdin — no shell, no
+	// R-861 (a) A1: the ROOT verb writes the file (it re-checks the ref — a compromised agent cannot hand the guest's
-	// interpolation, no `bash -c` (the only swap vector that would have needed an arbitrary-exec
+	// bootstrap another image). The bytes are `image\n`, byte-identical to the golden's `printf '%s\n'`; the bootstrap
-	// grant). The trailing "\n" makes the on-disk bytes byte-identical to the golden's
+	// reads `IMAGE=$(cat …)` so the newline is stripped on read. image is also strict-validated (controllerImageRe)
-	// `printf '%s\n'`; the bootstrap reads `IMAGE=$(cat …)` so the newline is stripped on read
+	// upstream in Swap.
-	// (spike SPIKE-controllerswap-narrow-grants-2026-06-29). image is strict-validated
+	return c.exec.WriteControllerImage(ctx, vmid, image)
-	// (controllerImageRe) upstream in Swap; defence-in-depth, the stdin path can't smuggle anyway.
-	_, err := c.exec.GuestExecStdin(ctx, vmid, strings.NewReader(image+"\n"), "tee", controllerImageFile)
-	return err
 }
 
 func (c *ControllerSwapper) restartBootstrap(ctx context.Context, vmid int) error {

internal/localapi/controllerswap_test.go

@@ -23,7 +23,7 @@ type fakeGuestExec struct {
 	present       map[string]bool // images pulled into the guest
 	good          map[string]bool // images that report healthy when running
 	containerImg  string          // image the running container currently has
-	teeStdin      []string        // raw bytes piped into each `tee` write (the swap's write vector)
+	teeStdin      []string        // image refs handed to WriteControllerImage (the root verb, R-861 (a) A1)
 	failRestart   bool
 	noHealthBlock bool // if set, .State.Health is absent ("none")
 	restartCount  int  // F1: .RestartCount reported by docker inspect (a crash-looper has >0)
@@ -75,20 +75,15 @@ func (f *fakeGuestExec) GuestExec(_ context.Context, _ int, args ...string) (str
 	return "", fmt.Errorf("fake: unexpected exec %v", args)
 }
 
-// GuestExecStdin models the swap's write vector: `tee /etc/felhom-controller-image` with the image
+// WriteControllerImage models the swap's write: the root verb `felhom-priv-apply controller-image <vmid>` (R-861
-// piped on stdin. It records the raw stdin bytes and sets the modeled file content (newline-stripped,
+// (a) A1). It records the ref and sets the modeled file content, as the bootstrap's `IMAGE=$(cat …)` would read it.
-// as the bootstrap's `IMAGE=$(cat …)` read would see it).
+func (f *fakeGuestExec) WriteControllerImage(_ context.Context, _ int, image string) error {
-func (f *fakeGuestExec) GuestExecStdin(_ context.Context, _ int, stdin io.Reader, args ...string) (string, error) {
 	f.mu.Lock()
 	defer f.mu.Unlock()
-	f.calls = append(f.calls, args)
+	f.calls = append(f.calls, []string{"felhom-priv-apply", "controller-image", image})
-	b, _ := io.ReadAll(stdin)
+	f.teeStdin = append(f.teeStdin, image+"\n")
-	if len(args) >= 2 && args[0] == "tee" && args[1] == controllerImageFile {
+	f.imageFile = image
-		f.teeStdin = append(f.teeStdin, string(b))
+	return nil
-		f.imageFile = strings.TrimSpace(string(b))
-		return string(b), nil // tee echoes stdin to stdout
-	}
-	return "", fmt.Errorf("fake: unexpected exec-stdin args=%v stdin=%q", args, string(b))
 }
 
 // wrote reports whether the image was written via the stdin `tee` vector with the exact `image\n`
@@ -162,7 +157,7 @@ func TestControllerSwap_Happy(t *testing.T) {
 
 // The write vector must be the stdin `tee` with byte-identical `image\n` and NO shell — the
 // controllerswap.go writeImage rewrite. This would FAIL on the pre-change `bash -c "printf … >"` impl.
-func TestControllerSwap_WriteViaStdinTee_NoShell(t *testing.T) {
+func TestControllerSwap_WriteViaRootVerb_NoShell(t *testing.T) {
 	fe := &fakeGuestExec{
 		imageFile: prevImg,
 		present:   map[string]bool{newImg: true},
@@ -173,22 +168,15 @@ func TestControllerSwap_WriteViaStdinTee_NoShell(t *testing.T) {
 		t.Fatalf("state = %q, want done", st.State)
 	}
 	if !fe.wrote(newImg) {
-		t.Errorf("expected a tee write of %q+\\n; teeStdin=%q", newImg, fe.teeStdin)
+		t.Errorf("expected the root verb to write %q; writes=%q", newImg, fe.teeStdin)
 	}
-	sawTee := false
 	for _, c := range fe.calls {
-		if len(c) >= 2 && c[0] == "tee" {
+		if len(c) >= 1 && c[0] == "tee" {
-			sawTee = true
+			t.Errorf("the swap still uses an in-guest tee (R-861 (a) A1 removed that grant): %v", c)
-			if c[1] != controllerImageFile {
-				t.Errorf("tee target = %q, want fixed %q", c[1], controllerImageFile)
-			}
 		}
 	}
-	if !sawTee {
-		t.Error("no tee call recorded — writeImage did not use the stdin tee vector")
-	}
 	if fe.usedShell() {
-		t.Errorf("swap used a shell vector (bash/-c/printf) — must be stdin tee only; calls=%v", fe.calls)
+		t.Errorf("swap used a shell vector (bash/-c/printf); calls=%v", fe.calls)
 	}
 }
 
@@ -300,9 +288,7 @@ func (s *inspectScript) GuestExec(_ context.Context, _ int, args ...string) (str
 	}
 	return "", nil
 }
-func (s *inspectScript) GuestExecStdin(_ context.Context, _ int, _ io.Reader, _ ...string) (string, error) {
+func (s *inspectScript) WriteControllerImage(context.Context, int, string) error { return nil }
-	return "", nil
-}
 
 func fastSwapper(exec GuestExecutor) *ControllerSwapper {
 	s := NewControllerSwapper(exec, "", discardLogger())

internal/localapi/escrow_recover.go

@@ -127,6 +127,22 @@ func (s *Server) handleRecoverOffsitePassword(w http.ResponseWriter, r *http.Req
 					"retained_has_restic_pw": match.HasResticPassword,
 				},
 				"the recovery code is correct, but it belongs to an EARLIER sealed package (superseded "+match.SupersededAt+"), not the one currently held")
+		// ── R-304 (2026-10-08) — NOT EVERY EARLIER PACKAGE WAS CHECKED. ─────────────────────────
+		//
+		// The current package refused the code, no retained package opened it — and at least one earlier
+		// package the hub holds was never tried (or the list could not be read). Saying „the code is
+		// wrong" here would claim a check that did not happen. 424 (Failed Dependency): the verdict
+		// depends on packages we could not try. The controller classifies on the status, never on this
+		// sentence; an older controller maps an unknown status to its neutral „we do not know why".
+		case errors.Is(err, escrow.ErrRetainedUnchecked):
+			n := -1
+			var ue *escrow.RetainedUncheckedError
+			if errors.As(err, &ue) {
+				n = ue.Unchecked
+			}
+			s.logger.Warn("local-api: offsite key recovery: the code did not open the current package and earlier packages were NOT all checked — not reported as a wrong code (R-304)", "vmid", vmid, "unchecked", n)
+			writeStatus(w, http.StatusFailedDependency, false, map[string]any{"older_unchecked": n},
+				"the recovery code did not open the current sealed package, and earlier packages the hub holds were not all checked — the code may belong to one of them; nothing was written")
 		case errors.Is(err, escrow.ErrNoResticPassword):
 			s.logger.Warn("local-api: offsite key recovery: the bundle opened but predates the repository-password field", "vmid", vmid)
 			writeErr(w, http.StatusConflict, "the recovery code opened the bundle, but it carries NO offsite repository password (sealed before that field existed; it cannot be retro-fitted)")

internal/localapi/escrow_recover_class_test.go

@@ -54,6 +54,13 @@ func TestRecoverOffsitePassword_EachSituationGetsItsOwnStatus(t *testing.T) {
 			wantStatus: 404,
 			mustNotSay: []string{"did not open"},
 		},
+		{
+			// R-304: earlier packages were not all tried — never „did not open the sealed bundle" (the wrong-code words).
+			name:       "earlier packages not all checked — not a wrong code",
+			err:        &escrow.RetainedUncheckedError{Unchecked: 2},
+			wantStatus: 424,
+			mustNotSay: []string{"did not open the sealed bundle", "could not be fetched"},
+		},
 		{
 			name:       "the bundle predates the repository-password field",
 			err:        escrow.ErrNoResticPassword,

internal/localapi/guestbind.go

@@ -3,7 +3,6 @@ package localapi
 import (
 	"context"
 	"fmt"
-	"io"
 	"log/slog"
 	"strconv"
 	"strings"
@@ -126,14 +125,16 @@ func (b *GuestBinder) GuestExec(ctx context.Context, vmid int, args ...string) (
 	return string(out), nil
 }
 
-// GuestExecStdin is GuestExec with the in-guest command's stdin fed from stdin. The controller-swap
+// privApplyBin is the root content checker (R-861); its `controller-image` verb writes the guest's image file.
-// write uses it to pipe the image ref into an in-guest `tee` (no shell vector, no interpolation),
+const privApplyBin = "/usr/local/sbin/felhom-priv-apply"
-// through the same fenced runner so the `sudo -n` prefix stays in one place.
+
-func (b *GuestBinder) GuestExecStdin(ctx context.Context, vmid int, stdin io.Reader, args ...string) (string, error) {
+// WriteControllerImage pipes `image\n` to `felhom-priv-apply controller-image <vmid>` through the same fenced runner
-	pctArgs := append([]string{"exec", strconv.Itoa(vmid), "--"}, args...)
+// (the `sudo -n` prefix stays in one place). The verb checks the ref as root and writes the guest file itself
-	out, stderr, err := b.runner.RunStdin(ctx, stdin, "pct", pctArgs...)
+// (R-861 (a) A1, `09` §3 decision 165). Pinned by TestR861_WriteControllerImageUsesTheRootVerb.
+func (b *GuestBinder) WriteControllerImage(ctx context.Context, vmid int, image string) error {
+	_, stderr, err := b.runner.RunStdin(ctx, strings.NewReader(image+"\n"), privApplyBin, "controller-image", strconv.Itoa(vmid))
 	if err != nil {
-		return string(out), fmt.Errorf("pct exec %d %v: %w: %s", vmid, args, err, strings.TrimSpace(string(stderr)))
+		return fmt.Errorf("felhom-priv-apply controller-image %d: %w: %s", vmid, err, strings.TrimSpace(string(stderr)))
 	}
-	return string(out), nil
+	return nil
 }

internal/localapi/r861_controller_image_test.go

@@ -0,0 +1,48 @@
+package localapi
+
+import (
+	"context"
+	"io"
+	"testing"
+)
+
+// stdinRecorder is a proxmox.Runner that records each call and the stdin it was handed.
+type stdinRecorder struct {
+	name  string
+	args  []string
+	stdin string
+}
+
+func (r *stdinRecorder) Run(_ context.Context, name string, args ...string) ([]byte, []byte, error) {
+	r.name, r.args = name, args
+	return nil, nil, nil
+}
+
+func (r *stdinRecorder) RunStdin(_ context.Context, stdin io.Reader, name string, args ...string) ([]byte, []byte, error) {
+	b, _ := io.ReadAll(stdin)
+	r.name, r.args, r.stdin = name, args, string(b)
+	return nil, nil, nil
+}
+
+// R-861 (a) A1 (`09` §3 decision 165): the managed controller update writes the guest's image file through the ROOT
+// verb, never through an in-guest `tee` the agent could feed any image.
+//
+// COMPANION RED-PROOF (observed): restore the pre-A1 body (`b.runner.RunStdin(ctx, …, "pct", "exec", vmid, "--",
+// "tee", controllerImageFile)`) → this fails with "the image write ran pct …, want felhom-priv-apply". Restored.
+func TestR861_WriteControllerImageUsesTheRootVerb(t *testing.T) {
+	rec := &stdinRecorder{}
+	b := NewGuestBinder(rec, discardLogger())
+	const img = "gitea.dooplex.hu/admin/felhom-controller:0.302.0"
+	if err := b.WriteControllerImage(context.Background(), 9201, img); err != nil {
+		t.Fatal(err)
+	}
+	if rec.name != privApplyBin {
+		t.Fatalf("the image write ran %s %v, want felhom-priv-apply", rec.name, rec.args)
+	}
+	if len(rec.args) != 2 || rec.args[0] != "controller-image" || rec.args[1] != "9201" {
+		t.Fatalf("argv = %v, want [controller-image 9201] (the sudoers line `^controller-image [0-9]+$`)", rec.args)
+	}
+	if rec.stdin != img+"\n" {
+		t.Fatalf("stdin = %q, want the ref plus one newline", rec.stdin)
+	}
+}

internal/localapi/server.go

@@ -825,6 +825,10 @@ func (s *Server) handleBackup(w http.ResponseWriter, r *http.Request, vmid int)
 		return
 	}
 	key := backupJobKey{vmid: vmid, target: tier.TargetID}
+	// R-899 (operator ruling 2026-10-08): a household press („Mentés most") is not the night's backup. A controller
+	// that knows sends `trigger=manual`; then the OS leg does not follow (it belongs to the night, after the night's
+	// own copy). An older controller sends nothing and keeps the old behaviour.
+	manual := r.URL.Query().Get("trigger") == "manual"
 
 	// ONE BACKUP AT A TIME PER GUEST, ACROSS ALL TIERS (operator ruling 2026-07-26: "other backup
 	// shouldn't start until finished"). vzdump takes a guest lock, so a concurrent second backup
@@ -926,7 +930,9 @@ func (s *Server) handleBackup(w http.ResponseWriter, r *http.Request, vmid int)
 		}
 		s.finishJob(key, jobID, b)
 		// OS leg (agent v0.140.0): after the night's whole-guest copy exists, still holding the heavy-op gate.
-		if b.Success && tier.Primary && s.afterPrimaryBackup != nil {
+		if b.Success && tier.Primary && s.afterPrimaryBackup != nil && manual {
+			s.logger.Info("local-api: no OS leg after a manual backup — it follows the night's own backup (R-899)", "vmid", vmid, "job", jobID)
+		} else if b.Success && tier.Primary && s.afterPrimaryBackup != nil {
 			s.afterPrimaryBackup(base, vmid)
 		}
 	}()

internal/osupdate/kernel.go

@@ -0,0 +1,446 @@
+package osupdate
+
+// The kernel lane (R-836, `09` §3 decisions 164 + 172, `11` §5.11). The root half is felhom-os-apply's layer "kernel"
+// (configs/, its own tests); this file decides WHEN and judges the boot:
+//
+//   - the night leg (Run → runKernel): after a healthy host step, on a night the hub marks as told (the household was
+//     mailed the day before — no mail, no step): ring 0 STAGES the pending kernel (select pending-kernel, the root-owned
+//     ring-0 mark) and reboots; ring 1 reboots only a step a signed os_kernel_step staged earlier (KernelStepExecutor).
+//   - after a boot (KernelAfterBoot, at daemon start): the wrapper says what became of the step. On the new kernel the
+//     agent JUDGES the boot — the host health rule (`11` §8.2: the Proxmox daemons, the guest running and healthy, the
+//     tunnel) AND the box reaching the hub — for KernelJudgeWait. Healthy → kernel-good (the new kernel becomes the
+//     default). Not healthy by the deadline → ONE self-revert (kernel-revert: a reboot into the old kernel, still the
+//     default). A crash on the new kernel needs nothing from the agent: GRUB already boots the old default.
+//
+// The host is rebooted by this file only through the wrapper (kernel-reboot, kernel-revert), and only for a staged step.
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"regexp"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
+)
+
+// OpKernelStep is the signed op class that STAGES a kernel set on a ring-1 box (it never reboots: the night leg does,
+// once the household was told). CC may sign it until the first paying customer (R-530 ruling).
+const OpKernelStep = "os_kernel_step"
+
+// DefaultKernelJudgeWait is how long a one-shot boot may take to come back healthy before the agent reverts it ONCE.
+// Measured 2026-10-07 (`audits/kernel-lane-2026-10-07/B/`): every container healthy 68 s after a reboot on demo-felhom,
+// 272 s on demo-hp; 20 minutes stays under the hub's 45-minute host_stale (a box that never comes back alarms after it).
+const DefaultKernelJudgeWait = 20 * time.Minute
+
+var kverRE = regexp.MustCompile(`^[0-9]+\.[0-9]+\.[0-9]+-[0-9]+-pve$`)
+
+// KernelView is the wrapper's kernel object (felhom-os-apply Kernel.view).
+type KernelView struct {
+	Running        string  `json:"running"`
+	Default        string  `json:"default"`
+	Flag           *string `json:"flag"`
+	Phase          string  `json:"phase"`
+	From           string  `json:"from"`
+	To             string  `json:"to"`
+	SelfRevertUsed bool    `json:"self_revert_used"`
+	Reason         string  `json:"reason"`
+	VMID           int     `json:"vmid"` // the customer guest the step was staged for (the health rule's guest)
+}
+
+// kernelReportRing is the ring an after-boot report carries. In the first second after a boot the agent has not
+// fetched the hub's block yet, and Block() then answers ring 1 — so a ring-0 box's „judging" report said ring 1
+// (seen on demo-felhom, 2026-10-08 night, `audits/kernel-night-2026-10-07/readback/`). Order: the fetched block; the
+// block the daemon saved on disk before the reboot (R-866); ring 1 as before. A label only: the hub's approval reads its
+// own ring list. Pinned by TestKernelReportRing_BeforeFirstFetch.
+func (l *Leg) kernelReportRing() int {
+	l.mu.Lock()
+	fetched := l.block
+	l.mu.Unlock()
+	if fetched != nil {
+		return fetched.Ring
+	}
+	if b, _, ok := LoadSavedBlock(l.planDir()); ok && b != nil {
+		return b.Ring
+	}
+	return 1
+}
+
+func parseKernel(raw json.RawMessage) KernelView {
+	var v KernelView
+	_ = json.Unmarshal(raw, &v)
+	return v
+}
+
+// kernelPlan is one kernel-layer wrapper call.
+func kernelPlan(mode string, vmid int, extra map[string]any) map[string]any {
+	p := map[string]any{"release_id": "kernel", "layer": LayerKernel, "lane": "slow", "vmid": vmid, "mode": mode,
+		"packages": []Package{}}
+	for k, v := range extra {
+		p[k] = v
+	}
+	return p
+}
+
+// KernelStatus reads the kernel lane's state (read only).
+func (l *Leg) KernelStatus(ctx context.Context, vmid int) (KernelView, error) {
+	wr, err := l.call(ctx, "kstatus"+l.now().UTC().Format("150405"), kernelPlan("kernel-status", vmid, nil))
+	if err != nil {
+		return KernelView{}, err
+	}
+	if wr.refused() {
+		return KernelView{}, fmt.Errorf("kernel-status refused: %s", wr.Refused)
+	}
+	return parseKernel(wr.Kernel), nil
+}
+
+// kernelDue reports whether tonight's leg may take a kernel step, and why not.
+func kernelDue(blk hub.WireOSUpdate, trigger string) (bool, string) {
+	switch {
+	case trigger != "night":
+		return false, "a kernel step runs only in the night leg (never a debug pass)"
+	case blk.Kernel == nil:
+		return false, "the hub names no kernel step for this box"
+	case !blk.Enabled:
+		return false, "OS updates are switched off for this box"
+	case !kverRE.MatchString(blk.Kernel.Kver):
+		return false, "the hub's kernel " + blk.Kernel.Kver + " is not a kernel version"
+	case !blk.Kernel.Tonight:
+		return false, "the household has not been told about tonight (no mail, no step — `09` §3 decision 172)"
+	}
+	return true, ""
+}
+
+// runKernel is the night leg's last step. It returns the stage report (Layer "" when nothing ran). On success the box
+// is rebooting when it returns.
+func (l *Leg) runKernel(ctx context.Context, runID string, vmid int, trigger string, blk hub.WireOSUpdate) Report {
+	lg := l.log().With("run", runID, "layer", LayerKernel, "vmid", vmid, "trigger", trigger, "ring", blk.Ring)
+	if ok, why := kernelDue(blk, trigger); !ok {
+		lg.Info("osupdate: kernel step skipped — " + why)
+		return Report{}
+	}
+	want := blk.Kernel.Kver
+	st, err := l.KernelStatus(ctx, vmid)
+	if err != nil {
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid,
+			Mode: "apply", Outcome: "failed", HealthReason: "kernel status unreadable: " + err.Error()})
+	}
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid, Mode: "apply", ReleaseID: want}
+	switch {
+	case st.Phase == "staged" && st.To == want:
+		lg.Info("osupdate: kernel step — a staged kernel waits for tonight", "from", st.From, "to", st.To)
+		rep.Outcome, rep.Healthy = "staged", true
+	case blk.Ring != 0:
+		lg.Info("osupdate: kernel step skipped — ring 1 boots only a kernel a signed os_kernel_step staged", "phase", st.Phase, "staged", st.To, "want", want)
+		return Report{}
+	default:
+		// R-898: EXACTLY the kernel the household was told about — never "whatever is pending tonight" (the sources can
+		// offer a newer one by night; the step then refused, R23, and the night was lost). A version no longer
+		// installable is refused by the wrapper before any change (R7) and the hub tells the household again.
+		wr, cerr := l.call(ctx, runID, kernelPlan("apply", vmid, map[string]any{"release_id": "ring0-" + runID,
+			"select": "listed", "packages": KernelSet(want), "expect_kver": want, "run_id": runID, "trigger": trigger,
+			"ring": blk.Ring}))
+		rep.unsent = reportFile(l.planDir(), runID, LayerKernel, "apply")
+		rep.Kernel = rawOrNil(wr.Kernel)
+		switch {
+		case cerr != nil:
+			rep.Outcome, rep.HealthReason = "failed", cerr.Error()
+			return l.finish(ctx, lg, rep)
+		case wr.refused():
+			rep.Outcome, rep.Refused = "refused", wr.Refused
+			return l.finish(ctx, lg, rep)
+		case wr.failed():
+			rep.Outcome, rep.Refused = "failed", wr.Failed
+			return l.finish(ctx, lg, rep)
+		case wr.OutcomeHint == "nothing" || len(wr.Upgraded) == 0:
+			rep.Outcome, rep.Healthy = "nothing", true
+			return l.finish(ctx, lg, rep)
+		}
+		rep.Outcome, rep.Healthy, rep.Upgraded, rep.Authority, rep.PassSeconds = "staged", true, wr.Upgraded, wr.Authority, wr.PassSeconds
+		rep.RebootNeeded = true
+	}
+	rep = l.finish(ctx, lg, rep) // the hub hears "staged" BEFORE the box goes down
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-reboot", vmid, nil))
+	switch {
+	case err != nil:
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid,
+			Mode: "kernel-reboot", ReleaseID: want, Outcome: "failed", HealthReason: "kernel-reboot: " + err.Error()})
+	case wr.refused() || wr.failed():
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: trigger, Ring: blk.Ring, VMID: vmid,
+			Mode: "kernel-reboot", ReleaseID: want, Outcome: "refused", Refused: firstRaw(wr.Refused, wr.Failed),
+			Kernel: rawOrNil(wr.Kernel)})
+	}
+	lg.Warn("osupdate: kernel step — the box restarts now for its one-shot boot", "to", want)
+	return rep
+}
+
+func firstRaw(a, b json.RawMessage) json.RawMessage {
+	if r := rawOrNil(a); r != nil {
+		return r
+	}
+	return rawOrNil(b)
+}
+
+// KernelJudge is what KernelAfterBoot needs besides the leg: the hub reachability probe is the "judging" report itself.
+type KernelJudge struct {
+	Wait time.Duration // default DefaultKernelJudgeWait
+	Poll time.Duration // default 30 s
+}
+
+// KernelAfterBoot runs once at daemon start: what became of a kernel step across the boot. On the new kernel it judges
+// the boot (blocking up to the wait — run it in a goroutine). vmid 0 = the guest the step recorded (it may not run yet).
+func (l *Leg) KernelAfterBoot(ctx context.Context, vmid int, j KernelJudge) Report {
+	runID := "boot-" + l.now().UTC().Format("20060102T150405Z")
+	lg := l.log().With("run", runID, "layer", LayerKernel, "vmid", vmid)
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-boot", vmid, nil))
+	if err != nil {
+		lg.Warn("osupdate: kernel after-boot check failed", "err", err)
+		return Report{}
+	}
+	if wr.refused() {
+		lg.Info("osupdate: kernel after-boot check refused (an older wrapper, or a BYO host)", "refused", string(wr.Refused))
+		return Report{}
+	}
+	v := parseKernel(wr.Kernel)
+	if vmid <= 0 {
+		vmid = v.VMID // after a boot the guest may not run yet — the step's own record names it
+	}
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid, Mode: "kernel-boot",
+		ReleaseID: v.To, Kernel: rawOrNil(wr.Kernel)}
+	switch wr.KernelEvent {
+	case "fell_back":
+		rep.Outcome, rep.HealthReason = "fell_back", v.Reason
+		lg.Warn("osupdate: kernel step FELL BACK — the new kernel did not come up; the box runs the old one", "from", v.From, "to", v.To)
+		return l.finish(ctx, lg, rep)
+	case "self_reverted":
+		rep.Outcome, rep.HealthReason = "self_reverted", v.Reason
+		lg.Warn("osupdate: kernel step SELF-REVERTED — back on the old kernel", "from", v.From, "to", v.To, "reason", v.Reason)
+		return l.finish(ctx, lg, rep)
+	case "revert_failed":
+		rep.Outcome, rep.HealthReason = "revert_failed", v.Reason
+		lg.Error("osupdate: kernel self-revert came back on the NEW kernel — no second revert; the operator decides", "to", v.To)
+		return l.finish(ctx, lg, rep)
+	case "judging":
+		return l.judgeKernel(ctx, runID, vmid, v, wr.HealthBefore, j, lg)
+	}
+	return Report{}
+}
+
+// KernelVerdict is THE one-shot boot rule (R-836; pinned by TestKernelVerdict): the host health rule (`11` §8.2 —
+// the Proxmox daemons and the agent active, the customer guest running and its own rule passing, the tunnel running)
+// AND the box reached the hub since this boot.
+func KernelVerdict(before, after *Health, tunnel string, hubReached bool) (bool, string) {
+	if ok, why := HostHealthVerdict(before, after, tunnel); !ok {
+		return false, why
+	}
+	if !hubReached {
+		return false, "the box has not reached the hub since the boot"
+	}
+	return true, ""
+}
+
+func (l *Leg) judgeKernel(ctx context.Context, runID string, vmid int, v KernelView, before *Health, j KernelJudge, lg *slog.Logger) Report {
+	wait, poll := j.Wait, j.Poll
+	if wait <= 0 {
+		wait = DefaultKernelJudgeWait
+	}
+	if poll <= 0 {
+		poll = 30 * time.Second
+	}
+	lg.Info("osupdate: kernel step — judging the one-shot boot", "from", v.From, "to", v.To, "wait", wait.String())
+	start := l.now()
+	deadline := start.Add(wait)
+	hubReached := false
+	var why string
+	for {
+		if !hubReached && l.Hub != nil {
+			// the hub's reachability IS this report reaching it (and the operator sees the box is back on the new kernel)
+			body, _ := json.Marshal(Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid,
+				Mode: "kernel-boot", ReleaseID: v.To, Outcome: "judging", Kernel: mustRaw(v)})
+			rctx, cancel := context.WithTimeout(ctx, 30*time.Second)
+			if err := l.Hub.PostOSReport(rctx, body); err == nil {
+				hubReached = true
+				lg.Info("osupdate: kernel step — the box reached the hub on the new kernel", "after", l.now().Sub(start).Round(time.Second).String())
+			}
+			cancel()
+		}
+		var h *Health
+		hr, err := l.call(ctx, runID, kernelPlan("health", vmid, nil))
+		switch {
+		case err != nil:
+			why = "no health reading: " + err.Error()
+		case hr.refused():
+			why = "no health reading: " + string(hr.Refused)
+		default:
+			h = hr.Health
+		}
+		if h != nil {
+			t := hub.TunnelUnknown
+			if l.Tunnel != nil {
+				t, _ = l.Tunnel.Status(ctx)
+			}
+			var ok bool
+			ok, why = KernelVerdict(before, h, t, hubReached)
+			if ok {
+				return l.kernelGood(ctx, runID, vmid, v, start, lg)
+			}
+		}
+		if !l.now().Before(deadline) || ctx.Err() != nil {
+			break
+		}
+		l.sleep(ctx, poll)
+	}
+	if ctx.Err() != nil {
+		lg.Warn("osupdate: kernel judging stopped (the agent is stopping) — the next start judges again", "reason", why)
+		return Report{}
+	}
+	// not healthy by the deadline: tell the hub (best effort), then ONE self-revert into the old kernel
+	rep := l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid,
+		Mode: "kernel-revert", ReleaseID: v.To, Outcome: "health_failed", HealthReason: why + " — reverting to " + v.From,
+		Kernel: mustRaw(v)})
+	lg.Error("osupdate: kernel step — the one-shot boot is NOT healthy; restarting ONCE into the old kernel", "reason", why,
+		"waited", wait.String(), "from", v.From, "to", v.To)
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-revert", vmid, map[string]any{"reason": truncate(why, 280)}))
+	if err != nil || wr.refused() || wr.failed() {
+		lg.Error("osupdate: kernel self-revert did not start — the box stays on the new kernel; the operator decides",
+			"err", err, "refused", string(firstRaw(wr.Refused, wr.Failed)))
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid,
+			Mode: "kernel-revert", ReleaseID: v.To, Outcome: "revert_failed", Refused: firstRaw(wr.Refused, wr.Failed),
+			HealthReason: "the self-revert did not start"})
+	}
+	return rep
+}
+
+func (l *Leg) kernelGood(ctx context.Context, runID string, vmid int, v KernelView, start time.Time, lg *slog.Logger) Report {
+	wr, err := l.call(ctx, runID, kernelPlan("kernel-good", vmid, nil))
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: "boot", Ring: l.kernelReportRing(), VMID: vmid, Mode: "kernel-good",
+		ReleaseID: v.To}
+	switch {
+	case err != nil:
+		rep.Outcome, rep.HealthReason = "failed", "kernel-good: "+err.Error()
+	case wr.refused() || wr.failed():
+		rep.Outcome, rep.Refused, rep.HealthReason = "failed", firstRaw(wr.Refused, wr.Failed), "kernel-good did not move the default"
+	default:
+		rep.Outcome, rep.Healthy = "applied", true
+		rep.HealthReason = fmt.Sprintf("healthy %s after the agent started; the new kernel is the default", l.now().Sub(start).Round(time.Second))
+	}
+	rep.Kernel = rawOrNil(wr.Kernel)
+	lg.Info("osupdate: kernel step — "+rep.Outcome, "to", v.To, "reason", rep.HealthReason)
+	return l.finish(ctx, lg, rep)
+}
+
+func mustRaw(v any) json.RawMessage {
+	b, _ := json.Marshal(v)
+	return b
+}
+
+func truncate(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n]
+}
+
+// KernelSet is the package set that installs exactly kver (R-898; the hub's kernelSet, field-exact): the series
+// meta-package and the signed image, both at the kernel's own version. Proxmox keeps old kernel versions in its archive.
+// nil for a string that is not a kernel version.
+func KernelSet(kver string) []Package {
+	m := kverSeriesRE.FindStringSubmatch(kver)
+	if m == nil {
+		return nil
+	}
+	v := kver[:len(kver)-len("-pve")]
+	return []Package{{Name: "proxmox-kernel-" + m[1], Version: v, Origin: PVEOrigin},
+		{Name: "proxmox-kernel-" + kver + "-signed", Version: v, Origin: PVEOrigin}}
+}
+
+var kverSeriesRE = regexp.MustCompile(`^([0-9]+\.[0-9]+)\.[0-9]+-[0-9]+-pve$`)
+
+// KernelStepParams are a signed os_kernel_step's params: the exact kernel set (the wrapper compares it with the plan).
+type KernelStepParams struct {
+	ReleaseID string    `json:"release_id"`
+	Packages  []Package `json:"packages"`
+	Kver      string    `json:"kver"`
+	VMID      int       `json:"vmid,omitempty"`
+}
+
+// KernelStepExecutor STAGES a verified os_kernel_step (signedjobs.Executor) under the heavy-op gate. It never reboots:
+// the night leg reboots a staged kernel on a night the household was told about.
+type KernelStepExecutor struct {
+	Leg   *Leg
+	Guest func(ctx context.Context) (int, error)
+	Gate  func(ctx context.Context) (release func(), err error)
+}
+
+// Execute implements signedjobs.Executor.
+func (e KernelStepExecutor) Execute(ctx context.Context, op string, params json.RawMessage) error {
+	if op != OpKernelStep {
+		return signedjobs.ErrNoExecutor
+	}
+	so, ok := signedjobs.SignedOpFrom(ctx)
+	if !ok {
+		return fmt.Errorf("os_kernel_step: no signed envelope in the context — the wrapper could not verify it")
+	}
+	var p KernelStepParams
+	if err := json.Unmarshal(params, &p); err != nil || len(p.Packages) == 0 || !kverRE.MatchString(p.Kver) {
+		return fmt.Errorf("os_kernel_step: params must name the kernel set and its kver: %v", err)
+	}
+	vmid := p.VMID
+	if vmid == 0 {
+		if e.Guest == nil {
+			return fmt.Errorf("os_kernel_step: no vmid and no guest finder")
+		}
+		v, err := e.Guest(ctx)
+		if err != nil {
+			return fmt.Errorf("os_kernel_step: find the customer guest: %w", err)
+		}
+		vmid = v
+	}
+	if e.Gate != nil {
+		release, err := e.Gate(ctx)
+		if err != nil {
+			return fmt.Errorf("os_kernel_step: heavy-op gate busy (a backup or restore-test runs): %w", err)
+		}
+		defer release()
+	}
+	rep := e.Leg.StageKernelSigned(ctx, vmid, p, so.Blob, string(so.Sig))
+	if rep.Outcome == "staged" || rep.Outcome == "nothing" {
+		return nil
+	}
+	return fmt.Errorf("os_kernel_step: %s (%s) %s", rep.Outcome, rep.HealthReason, string(rep.Refused))
+}
+
+// StageKernelSigned stages a signed kernel set (ring 1): install + flag, no reboot.
+func (l *Leg) StageKernelSigned(ctx context.Context, vmid int, p KernelStepParams, blob []byte, sig string) Report {
+	unlock := l.lockPass(true)
+	defer unlock()
+	l.sendUnsentLocked(ctx) // R-868
+	runID := l.now().UTC().Format("20060102T150405Z")
+	rid := p.ReleaseID
+	if rid == "" {
+		rid = "signed-" + runID
+	}
+	lg := l.log().With("run", runID, "layer", LayerKernel, "vmid", vmid, "trigger", "signed", "release", rid)
+	wr, err := l.call(ctx, runID, kernelPlan("apply", vmid, map[string]any{"release_id": rid, "select": "listed",
+		"packages": p.Packages, "expect_kver": p.Kver, "run_id": runID, "trigger": "signed", "ring": l.Block().Ring,
+		"signed": map[string]string{"blob_b64": base64.StdEncoding.EncodeToString(blob), "sig": sig}}))
+	rep := Report{RunID: runID, Layer: LayerKernel, Trigger: "signed", Ring: l.Block().Ring, VMID: vmid, Mode: "apply",
+		ReleaseID: rid, Kernel: rawOrNil(wr.Kernel), unsent: reportFile(l.planDir(), runID, LayerKernel, "apply")}
+	switch {
+	case err != nil:
+		rep.Outcome, rep.HealthReason = "failed", err.Error()
+	case wr.refused():
+		rep.Outcome, rep.Refused = "refused", wr.Refused
+	case wr.failed():
+		rep.Outcome, rep.Refused = "failed", wr.Failed
+	case wr.OutcomeHint == "nothing" || len(wr.Upgraded) == 0:
+		rep.Outcome, rep.Healthy = "nothing", true
+	default:
+		rep.Outcome, rep.Healthy, rep.Upgraded, rep.Authority, rep.PassSeconds = "staged", true, wr.Upgraded, wr.Authority, wr.PassSeconds
+		rep.RebootNeeded = true
+	}
+	return l.finish(ctx, lg, rep)
+}

internal/osupdate/kernel_test.go

@@ -0,0 +1,328 @@
+package osupdate
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/reconcile"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
+)
+
+// ---- the kernel lane (R-836, `09` §3 decision 172, `11` §5.11) ----
+
+const kOld, kNew = "7.0.2-6-pve", "7.0.14-22-pve"
+
+func kview(phase string) json.RawMessage {
+	return mustRaw(KernelView{Running: kOld, Default: kOld, Phase: phase, From: kOld, To: kNew, VMID: 9201})
+}
+
+func tonight(ring int) *hub.WireOSUpdate {
+	return &hub.WireOSUpdate{Ring: ring, Enabled: true, Kernel: &hub.WireKernelStep{Kver: kNew, Tonight: true}}
+}
+
+func kernelCalls(w *fakeWrapper) []string {
+	var m []string
+	for _, p := range w.plans {
+		if p["layer"] == LayerKernel {
+			m = append(m, p["mode"].(string))
+		}
+	}
+	return m
+}
+
+// Ring 0, a told night: after the healthy host step the leg stages the pending kernel (select pending-kernel, the
+// kernel the household was told about), tells the hub "staged", THEN reboots — the kernel step ends the night.
+func TestKernel_Ring0ToldNightStagesThenReboots(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{
+		"kernel-status": {{Kernel: kview("none")}},
+		"apply":         {{Upgraded: []Package{{Name: "proxmox-kernel-7.0", Version: "7.0.14-22"}}, Authority: "ring0", Kernel: kview("staged")}},
+		"kernel-reboot": {{Kernel: kview("oneshot")}},
+	}}
+	l, h := newLeg(t, w, tonight(0))
+	p := l.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-status,apply,kernel-reboot" {
+		t.Fatalf("kernel calls = %s", got)
+	}
+	var ap map[string]any
+	for _, x := range w.plans {
+		if x["layer"] == LayerKernel && x["mode"] == "apply" {
+			ap = x
+		}
+	}
+	// R-898: EXACTLY the told kernel — the listed set derived from it, never "pending" (red before the fix: select was
+	// pending-kernel, so a newer kernel in the sources by night was refused R23 and the night was lost)
+	pk, _ := json.Marshal(ap["packages"])
+	if ap["select"] != "listed" || ap["expect_kver"] != kNew || ap["lane"] != "slow" ||
+		string(pk) != `[{"name":"proxmox-kernel-7.0","origin":"Proxmox Debian Repository","version":"7.0.14-22"},{"name":"proxmox-kernel-7.0.14-22-pve-signed","origin":"Proxmox Debian Repository","version":"7.0.14-22"}]` {
+		t.Fatalf("stage plan = %v (packages %s)", ap, pk)
+	}
+	if p.Kernel.Outcome != "staged" || !p.Kernel.Healthy {
+		t.Fatalf("kernel report = %+v", p.Kernel)
+	}
+	last := h.reports[len(h.reports)-1]
+	if last.Layer != LayerKernel || last.Outcome != "staged" {
+		t.Fatalf("the hub must hear 'staged' before the reboot: %+v", h.reports)
+	}
+	// the kernel step is the LAST wrapper call of the night
+	if lp := w.plans[len(w.plans)-1]; lp["layer"] != LayerKernel || lp["mode"] != "kernel-reboot" {
+		t.Fatalf("the reboot must end the night, last call = %v", lp)
+	}
+}
+
+// No mail, no step: a kernel the household was NOT told about never runs; nor in a debug pass; nor without a block.
+// COMPANION RED-PROOF (observed): drop the `!blk.Kernel.Tonight` case in kernelDue → the first sub-case fails.
+func TestKernel_NoMailNoStep(t *testing.T) {
+	cases := map[string]struct {
+		blk     *hub.WireOSUpdate
+		trigger string
+	}{
+		"not told":   {&hub.WireOSUpdate{Ring: 0, Enabled: true, Kernel: &hub.WireKernelStep{Kver: kNew, Tonight: false}}, "night"},
+		"debug pass": {tonight(0), "debug"},
+		"no block":   {&hub.WireOSUpdate{Ring: 0, Enabled: true}, "night"},
+		"switch off": {&hub.WireOSUpdate{Ring: 0, Enabled: false, Kernel: &hub.WireKernelStep{Kver: kNew, Tonight: true}}, "night"},
+		"bad kver":   {&hub.WireOSUpdate{Ring: 0, Enabled: true, Kernel: &hub.WireKernelStep{Kver: "7.0; reboot", Tonight: true}}, "night"},
+	}
+	for name, c := range cases {
+		w := &fakeWrapper{t: t}
+		l, _ := newLeg(t, w, c.blk)
+		p := l.Run(context.Background(), 9201, c.trigger)
+		if len(kernelCalls(w)) != 0 || p.Kernel.Layer != "" {
+			t.Fatalf("%s: a kernel step ran: %v", name, kernelCalls(w))
+		}
+	}
+}
+
+// The kernel step needs a healthy host step on an appliance, and a healthy Proxmox step when one ran.
+func TestKernel_SkippedWithoutHealthyEarlierSteps(t *testing.T) {
+	w := &fakeWrapper{t: t}
+	l, _ := newLeg(t, w, tonight(0))
+	l.Appliance = false
+	l.Run(context.Background(), 9201, "night")
+	if len(kernelCalls(w)) != 0 {
+		t.Fatalf("a BYO box took a kernel step: %v", kernelCalls(w))
+	}
+	w2 := &fakeWrapper{t: t, applyRep: map[string]WrapperReport{LayerPVE: {Upgraded: []Package{{Name: "pve-manager", Version: "9.2.21"}},
+		PVEManager: "9.2.2"}}} // pveversion still old → the pve step is unhealthy
+	l2, _ := newLeg(t, w2, tonight(0))
+	l2.Run(context.Background(), 9201, "night")
+	if len(kernelCalls(w2)) != 0 {
+		t.Fatalf("a kernel step ran after an unhealthy Proxmox step: %v", kernelCalls(w2))
+	}
+}
+
+// Ring 1 reboots only a kernel a signed job staged — never stages one itself in the night leg.
+func TestKernel_Ring1RebootsOnlyASignedStage(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-status": {{Kernel: kview("none")}}}}
+	l, _ := newLeg(t, w, tonight(1))
+	l.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-status" {
+		t.Fatalf("ring 1 without a staged kernel: calls = %s", got)
+	}
+	w2 := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-status": {{Kernel: kview("staged")}},
+		"kernel-reboot": {{Kernel: kview("oneshot")}}}}
+	l2, _ := newLeg(t, w2, tonight(1))
+	p := l2.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w2), ","); got != "kernel-status,kernel-reboot" || p.Kernel.Outcome != "staged" {
+		t.Fatalf("ring 1 with a staged kernel: calls = %s report = %+v", got, p.Kernel)
+	}
+}
+
+// A refused stage never reboots.
+func TestKernel_RefusedStageNeverReboots(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-status": {{Kernel: kview("none")}},
+		"apply": {{Refused: json.RawMessage(`{"code":"R20","reason":"/boot/efi is not a mounted vfat ESP"}`)}}}}
+	l, h := newLeg(t, w, tonight(0))
+	p := l.Run(context.Background(), 9201, "night")
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-status,apply" || p.Kernel.Outcome != "refused" {
+		t.Fatalf("calls = %s report = %+v", got, p.Kernel)
+	}
+	if last := h.reports[len(h.reports)-1]; last.Layer != LayerKernel || last.Outcome != "refused" {
+		t.Fatalf("the hub must hear the refusal: %+v", last)
+	}
+}
+
+// THE one-shot boot rule: the host rule AND the hub reached. COMPANION RED-PROOF (observed): drop the hubReached
+// check in KernelVerdict → the second case fails.
+func TestKernelVerdict(t *testing.T) {
+	if ok, why := KernelVerdict(hostOK(), hostOK(), hub.TunnelRunning, true); !ok {
+		t.Fatalf("a healthy boot read unhealthy: %s", why)
+	}
+	if ok, why := KernelVerdict(hostOK(), hostOK(), hub.TunnelRunning, false); ok || !strings.Contains(why, "hub") {
+		t.Fatalf("a box that has not reached the hub must not pass: ok=%v %q", ok, why)
+	}
+	down := hostOK()
+	down.GuestRunning = new(bool)
+	if ok, _ := KernelVerdict(hostOK(), down, hub.TunnelRunning, true); ok {
+		t.Fatal("a guest that does not run must fail")
+	}
+	if ok, _ := KernelVerdict(hostOK(), hostOK(), hub.TunnelUnknown, true); ok {
+		t.Fatal("an unknown tunnel must fail (the host rule)")
+	}
+}
+
+func judgingLeg(t *testing.T, w *fakeWrapper) (*Leg, *fakeHub) {
+	if w.kernelRep == nil {
+		w.kernelRep = map[string][]WrapperReport{}
+	}
+	if _, ok := w.kernelRep["kernel-boot"]; !ok {
+		w.kernelRep["kernel-boot"] = []WrapperReport{{KernelEvent: "judging", Kernel: mustRaw(KernelView{Running: kNew,
+			Default: kOld, Phase: "judging", From: kOld, To: kNew, VMID: 9201}), HealthBefore: hostOK()}}
+	}
+	return newLeg(t, w, &hub.WireOSUpdate{Ring: 0, Enabled: true})
+}
+
+// A healthy one-shot boot: the hub hears "judging", then kernel-good, then "applied".
+func TestKernelAfterBoot_HealthyBecomesTheDefault(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-good": {{Kernel: kview("good")}}}}
+	l, h := judgingLeg(t, w)
+	r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{Wait: 10 * time.Minute, Poll: 30 * time.Second})
+	if got := strings.Join(kernelCalls(w), ","); got != "kernel-boot,health,kernel-good" {
+		t.Fatalf("calls = %s", got)
+	}
+	if r.Outcome != "applied" || !r.Healthy {
+		t.Fatalf("report = %+v", r)
+	}
+	if len(h.reports) != 2 || h.reports[0].Outcome != "judging" || h.reports[1].Outcome != "applied" {
+		t.Fatalf("hub reports = %+v", h.reports)
+	}
+	if w.plans[1]["vmid"] != float64(9201) {
+		t.Fatalf("the health reading must use the step's own guest, got %v", w.plans[1]["vmid"])
+	}
+}
+
+// An unhealthy one-shot boot: wait the full judge time, tell the hub, then ONE kernel-revert.
+// COMPANION RED-PROOF (observed): return before the kernel-revert call in judgeKernel → "calls" fails.
+func TestKernelAfterBoot_UnhealthyRevertsOnceAfterTheWait(t *testing.T) {
+	down := hostOK()
+	down.GuestRunning = new(bool)
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"health": {{Health: down}},
+		"kernel-revert": {{Kernel: kview("reverting")}}}}
+	l, h := judgingLeg(t, w)
+	start := l.now()
+	r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{Wait: 10 * time.Minute, Poll: time.Minute})
+	calls := kernelCalls(w)
+	if calls[len(calls)-1] != "kernel-revert" || strings.Count(strings.Join(calls, ","), "kernel-revert") != 1 {
+		t.Fatalf("calls = %v", calls)
+	}
+	if waited := l.now().Sub(start); waited < 10*time.Minute {
+		t.Fatalf("reverted after %s — before the judge wait", waited)
+	}
+	if r.Outcome != "health_failed" || !strings.Contains(r.HealthReason, "not running") {
+		t.Fatalf("report = %+v", r)
+	}
+	if last := h.reports[len(h.reports)-1]; last.Outcome != "health_failed" {
+		t.Fatalf("the hub must hear health_failed before the revert reboot: %+v", h.reports)
+	}
+	for _, p := range w.plans {
+		if p["mode"] == "kernel-revert" && !strings.Contains(p["reason"].(string), "not running") {
+			t.Fatalf("the revert must carry the reason: %v", p)
+		}
+	}
+}
+
+// A box that never reaches the hub is not "healthy" — it reverts too.
+func TestKernelAfterBoot_NoHubMeansRevert(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-revert": {{Kernel: kview("reverting")}}}}
+	l, _ := judgingLeg(t, w)
+	l.Hub = unreachableHub{}
+	l.KernelAfterBoot(context.Background(), 0, KernelJudge{Wait: 5 * time.Minute, Poll: time.Minute})
+	if c := kernelCalls(w); c[len(c)-1] != "kernel-revert" {
+		t.Fatalf("calls = %v", c)
+	}
+}
+
+type unreachableHub struct{}
+
+func (unreachableHub) PostOSReport(context.Context, []byte) error { return context.DeadlineExceeded }
+
+// What kernel-boot found becomes the hub's outcome, with no judging and no reboot.
+func TestKernelAfterBoot_FallBackAndRevertResultsAreReported(t *testing.T) {
+	for ev, want := range map[string]string{"fell_back": "fell_back", "self_reverted": "self_reverted", "revert_failed": "revert_failed"} {
+		w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-boot": {{KernelEvent: ev,
+			Kernel: mustRaw(KernelView{Running: kOld, Default: kOld, Phase: ev, From: kOld, To: kNew, Reason: "r", VMID: 9201})}}}}
+		l, h := judgingLeg(t, w)
+		r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{})
+		if r.Outcome != want || len(h.reports) != 1 || h.reports[0].Outcome != want {
+			t.Fatalf("%s: report %+v hub %+v", ev, r, h.reports)
+		}
+		if got := strings.Join(kernelCalls(w), ","); got != "kernel-boot" {
+			t.Fatalf("%s: calls = %s", ev, got)
+		}
+	}
+	// nothing to do → nothing reported
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"kernel-boot": {{KernelEvent: "none", Kernel: kview("good")}}}}
+	l, h := judgingLeg(t, w)
+	if r := l.KernelAfterBoot(context.Background(), 0, KernelJudge{}); r.Layer != "" || len(h.reports) != 0 {
+		t.Fatalf("an ordinary boot must report nothing: %+v %+v", r, h.reports)
+	}
+}
+
+// The signed executor STAGES (listed + the raw envelope + the kver) and never reboots.
+func TestKernelStepExecutor_StagesNeverReboots(t *testing.T) {
+	w := &fakeWrapper{t: t, kernelRep: map[string][]WrapperReport{"apply": {{Upgraded: []Package{{Name: "proxmox-kernel-7.0",
+		Version: "7.0.14-22"}}, Authority: "signed", Kernel: kview("staged")}}}}
+	l, h := newLeg(t, w, &hub.WireOSUpdate{Ring: 1, Enabled: true})
+	e := KernelStepExecutor{Leg: l, Guest: func(context.Context) (int, error) { return 9201, nil }}
+	params, _ := json.Marshal(KernelStepParams{ReleaseID: "os-kernel-1", Kver: kNew,
+		Packages: []Package{{Name: "proxmox-kernel-7.0", Version: "7.0.14-22", Origin: PVEOrigin}}})
+	ctx := signedjobs.WithSignedOp(context.Background(), &reconcile.SignedOp{Blob: []byte(`{"op":"os_kernel_step"}`), Sig: []byte("SIG")})
+	if err := e.Execute(ctx, OpKernelStep, params); err != nil {
+		t.Fatal(err)
+	}
+	pp := w.plans[len(w.plans)-1]
+	sg, _ := pp["signed"].(map[string]any)
+	if pp["mode"] != "apply" || pp["select"] != "listed" || pp["expect_kver"] != kNew || sg == nil ||
+		sg["blob_b64"] != base64.StdEncoding.EncodeToString([]byte(`{"op":"os_kernel_step"}`)) {
+		t.Fatalf("plan = %v", pp)
+	}
+	if got := strings.Join(kernelCalls(w), ","); got != "apply" {
+		t.Fatalf("a signed stage must never reboot: %s", got)
+	}
+	if len(h.reports) != 1 || h.reports[0].Outcome != "staged" {
+		t.Fatalf("hub = %+v", h.reports)
+	}
+	if err := e.Execute(context.Background(), OpKernelStep, params); err == nil {
+		t.Fatal("no envelope must refuse")
+	}
+	bad, _ := json.Marshal(KernelStepParams{Kver: "x", Packages: []Package{{Name: "a"}}})
+	if err := e.Execute(ctx, OpKernelStep, bad); err == nil {
+		t.Fatal("a bad kver must refuse")
+	}
+	if err := e.Execute(ctx, OpPVEStep, params); err != signedjobs.ErrNoExecutor {
+		t.Fatalf("another op must pass through the chain: %v", err)
+	}
+}
+
+// os_kernel_step is never benign.
+func TestKernelStep_IsDestructiveClass(t *testing.T) {
+	if reconcile.Classify(reconcile.ClassOSKernelStep, reconcile.Provenance{}) != reconcile.Destructive {
+		t.Fatal("os_kernel_step must be destructive-class (signed, operational key)")
+	}
+}
+
+// A kept stage report (the agent was killed mid-stage) reaches the hub as "staged" with its kernel view.
+func TestKernel_KeptStageReportIsStaged(t *testing.T) {
+	w := &fakeWrapper{t: t}
+	l, _ := newLeg(t, w, tonight(0))
+	ring := 0
+	rep := l.reportFromKept(context.Background(), WrapperReport{Layer: LayerKernel, Mode: "apply", Ring: &ring,
+		Upgraded: []Package{{Name: "proxmox-kernel-7.0", Version: "7.0.14-22"}}, Kernel: kview("staged")}, "/x/report-r-kernel-apply.json")
+	if rep.Outcome != "staged" || !rep.Healthy || len(rep.Kernel) == 0 {
+		t.Fatalf("kept = %+v", rep)
+	}
+}
+
+func TestKernelSet(t *testing.T) {
+	if got := KernelSet("7.0.14-20-pve"); len(got) != 2 || got[0].Name != "proxmox-kernel-7.0" || got[0].Version != "7.0.14-20" ||
+		got[1].Name != "proxmox-kernel-7.0.14-20-pve-signed" {
+		t.Fatalf("%+v", got)
+	}
+	if KernelSet("7.0; reboot") != nil || KernelSet("") != nil {
+		t.Fatal("a non-kernel string must give no set")
+	}
+}

internal/osupdate/leg.go

@@ -20,6 +20,7 @@ import (
 	"log/slog"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 	"sync"
@@ -27,6 +28,7 @@ import (
 
 	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/pvegate"
 )
 
 // WrapperPath is the pinned sudoers vector (configs/felhom-agent.sudoers FELHOM_OSAPPLY).
@@ -40,8 +42,24 @@ const (
 	LayerGuest  = "guest"
 	LayerHost   = "host"
 	LayerDocker = "docker" // the guest's Docker engine set — slow lane (`11` §5.8)
+	// LayerPVE is the HOST's Proxmox userspace packages — slow lane (R-812 option A, `09` §3 decision 163, `11` §5.10):
+	// ring 0 in the night leg after a healthy host step, ring 1 only inside a signed os_pve_step. Never a kernel.
+	LayerPVE = "pve"
+	// LayerKernel is the HOST's kernel — the kernel lane (R-836, `09` §3 decision 172, `11` §5.11): a one-shot boot of
+	// the new kernel through the ESP flag, the default moved only after a healthy boot (kernel.go).
+	LayerKernel = "kernel"
 )
 
+// PVEOrigin is the origin apt prints for download.proxmox.com (the wrapper's PVE_ORIGIN); InstalledPVEOrigin is how
+// the wrapper's inventory names the same source.
+const (
+	PVEOrigin          = "Proxmox Debian Repository"
+	InstalledPVEOrigin = "Proxmox"
+)
+
+// hostSlowRE mirrors the wrapper's HOST_SLOW_RE: kernel, boot, firmware and microcode names never ride the pve lane.
+var hostSlowRE = regexp.MustCompile(`^(linux-(image|headers|kbuild|modules|base)|proxmox-kernel|proxmox-default-kernel|pve-kernel|pve-firmware|firmware-|grub|shim|systemd-boot|intel-microcode|amd64-microcode|efibootmgr)`)
+
 // DockerNames are the six packages of the Docker engine set (the wrapper's DOCKER_NAMES).
 var DockerNames = map[string]bool{"containerd.io": true, "docker-buildx-plugin": true, "docker-ce": true,
 	"docker-ce-cli": true, "docker-ce-rootless-extras": true, "docker-compose-plugin": true}
@@ -109,6 +127,13 @@ type WrapperReport struct {
 	// OOMCheck (R-528, `09` decision 157): the docker layer's memory-kill check, {result, oom_killed, oom_event,
 	// exit_code, image, detail}. Carried to the hub UNCHANGED; the agent never reads it.
 	OOMCheck json.RawMessage `json:"oom_check"`
+	// PVEManager: the pve layer — pveversion's pve-manager version after the step ("unknown" = unreadable).
+	PVEManager string `json:"pve_manager"`
+	// Kernel (R-836): the kernel layer's view {running, default, flag, phase, from, to, …}; KernelEvent what kernel-boot
+	// found after a boot; OutcomeHint "nothing" when no kernel was pending.
+	Kernel      json.RawMessage `json:"kernel"`
+	KernelEvent string          `json:"kernel_event"`
+	OutcomeHint string          `json:"outcome_hint"`
 	// R-868 (v0.144.0): the agent's ids, echoed from the plan, so a report kept on disk can be sent without the
 	// agent process that started the pass. ReleaseID / VMID were always in the report.
 	RunID     string `json:"run_id"`
@@ -149,6 +174,12 @@ type Report struct {
 	// OOMCheck: docker layer — the wrapper's oom_check object, byte-for-byte (R-528; the hub decides approval on it).
 	// Pinned by TestDocker_OOMCheckReachesTheHubUnchanged and TestR868_KeptCopyCarriesTheOOMCheck.
 	OOMCheck json.RawMessage `json:"oom_check,omitempty"`
+	// PVEManager: pve layer — pve-manager's version after the step (the hub's System page; R-812 option A).
+	PVEManager string `json:"pve_manager,omitempty"`
+	// Kernel: kernel layer — the wrapper's kernel view, byte for byte (running, default, flag, phase, from, to). The
+	// outcomes of this layer: staged | applied (the new kernel is the default) | fell_back | health_failed (self-revert
+	// started) | self_reverted | revert_failed | judging | nothing | refused | failed.
+	Kernel json.RawMessage `json:"kernel,omitempty"`
 
 	unsent string // R-868: the wrapper's kept copy of this pass's report — deleted once the hub has it
 }
@@ -386,6 +417,36 @@ func EngineOf(pkgVersion string) string {
 	return v
 }
 
+// PVEHealthVerdict is THE Proxmox-package-step health rule (R-812 option A; pinned by TestPVEHealthVerdict): the host
+// rule (every host service active, the guest running and healthy, the tunnel running), plus every container running at
+// the start still runs as the SAME container (a Proxmox step must not restart the household's apps), plus pveversion
+// now reports the pve-manager the step installed (wantPVE "" = pve-manager was not in the step).
+func PVEHealthVerdict(before, after *Health, tunnel, wantPVE, gotPVE string) (bool, string) {
+	if ok, why := HostHealthVerdict(before, after, tunnel); !ok {
+		return false, why
+	}
+	if before != nil && before.Guest != nil && after.Guest != nil {
+		names := make([]string, 0, len(before.Guest.Containers))
+		for n := range before.Guest.Containers {
+			names = append(names, n)
+		}
+		sort.Strings(names)
+		for _, n := range names {
+			b := before.Guest.Containers[n]
+			if b.State != "running" || b.ID == "" {
+				continue
+			}
+			if a := after.Guest.Containers[n]; a.ID != b.ID {
+				return false, n + " is a new container (id changed) — the Proxmox step restarted the household's app"
+			}
+		}
+	}
+	if wantPVE != "" && gotPVE != wantPVE {
+		return false, "pveversion reads pve-manager " + gotPVE + ", not " + wantPVE
+	}
+	return true, ""
+}
+
 // DockerHealthVerdict is THE Docker-step health rule (`11` §5.8; pinned by TestDockerHealthVerdict): the guest rule,
 // plus every container running at the start still runs as the SAME container (same id — a changed id means the
 // household's apps restarted, which `live-restore` exists to prevent), plus the engine now reports the version the step
@@ -451,7 +512,7 @@ func (l *Leg) call(ctx context.Context, runID string, plan map[string]any) (Wrap
 
 // Pass is one leg's reports; an empty Layer means the step did not run.
 type Pass struct {
-	Guest, Host, Docker Report
+	Guest, Host, Docker, PVE, Kernel Report
 }
 
 // Run is one pass: the guest layer, then (on an appliance, after a good guest step) the host layer, then (ring 0
@@ -479,13 +540,54 @@ func (l *Leg) Run(ctx context.Context, vmid int, trigger string) Pass {
 		if err := l.EnsureLiveRestore(ctx, g.RunID, vmid); err != nil {
 			p.Docker = l.finish(ctx, lg, Report{RunID: g.RunID, Layer: LayerDocker, Trigger: trigger, Ring: 0, VMID: vmid,
 				Mode: "apply", Outcome: "failed", HealthReason: "live-restore could not be turned on: " + err.Error()})
-			return p
+		} else {
+			p.Docker = l.runLayer(ctx, g.RunID, LayerDocker, vmid, trigger, blk, dockerOpts{})
 		}
-		p.Docker = l.runLayer(ctx, g.RunID, LayerDocker, vmid, trigger, blk, dockerOpts{})
+	}
+	// R-812 option A: the Proxmox package step — ring 0, an appliance, after a HEALTHY host step (it is a host change).
+	// A Docker step's outcome does not gate it (the Docker set lives in the guest). Pinned by TestPVE_*.
+	switch {
+	case blk.Ring != 0 || !blk.Enabled:
+		lg.Info("osupdate: pve step skipped — ring 1 takes a Proxmox set only inside a signed operator job (`11` §5.10)", "ring", blk.Ring, "enabled", blk.Enabled)
+	case !l.Appliance || h.Layer == "" || !okStep(h):
+		lg.Info("osupdate: pve step skipped — no healthy host step this pass (an appliance only)", "appliance", l.Appliance, "host_outcome", h.Outcome)
+	default:
+		p.PVE = l.runPVE(ctx, g.RunID, vmid, trigger, blk, dockerOpts{})
+	}
+	// R-836 (`09` §3 decision 172): the kernel step ENDS the night — an appliance, after a healthy host step (and a
+	// healthy Proxmox step when one ran), only on a night the hub marks as told. It reboots the box. Pinned by TestKernel_*.
+	switch {
+	case !l.Appliance || h.Layer == "" || !okStep(h):
+		lg.Info("osupdate: kernel step skipped — no healthy host step this pass (an appliance only)", "appliance", l.Appliance, "host_outcome", h.Outcome)
+	case p.PVE.Layer != "" && !okStep(p.PVE):
+		lg.Warn("osupdate: kernel step skipped — the Proxmox step did not end healthy", "pve_outcome", p.PVE.Outcome)
+	default:
+		p.Kernel = l.runKernel(ctx, g.RunID, vmid, trigger, blk)
 	}
 	return p
 }
 
+// pveDrainWait bounds how long a pve step waits for the agent's own /etc/pve writes in flight (pvegate).
+var pveDrainWait = 2 * time.Minute
+
+// runPVE runs the pve layer while holding pvegate: the agent's own /etc/pve writes wait until it ends.
+func (l *Leg) runPVE(ctx context.Context, runID string, vmid int, trigger string, blk hub.WireOSUpdate, do dockerOpts) Report {
+	lg := l.log().With("run", runID, "layer", LayerPVE, "vmid", vmid, "trigger", trigger)
+	dctx, cancel := context.WithTimeout(ctx, pveDrainWait)
+	end, err := pvegate.Step(dctx)
+	cancel()
+	if err != nil {
+		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerPVE, Trigger: trigger, Ring: blk.Ring, VMID: vmid, Mode: "apply",
+			ReleaseID: do.releaseID, Outcome: "failed", HealthReason: "an agent write to /etc/pve did not finish in time (pvegate): " + err.Error()})
+	}
+	lg.Info("osupdate: pve step holds the /etc/pve write gate — the agent's own writes wait until it ends")
+	defer func() {
+		end()
+		lg.Info("osupdate: pve step released the /etc/pve write gate")
+	}()
+	return l.runLayer(ctx, runID, LayerPVE, vmid, trigger, blk, do)
+}
+
 // dockerOpts is a signed Docker step (DockerStepExecutor); the zero value is ring 0's unsigned "pending-docker".
 type dockerOpts struct {
 	releaseID string
@@ -571,7 +673,7 @@ func (l *Leg) runLayer(ctx context.Context, runID, layer string, vmid int, trigg
 		wire = blk.HostRelease
 	}
 	lane := "fast"
-	if layer == LayerDocker {
+	if layer == LayerDocker || layer == LayerPVE {
 		lane = "slow"
 		if do.signed != nil {
 			rel = hub.WireOSRelease{ID: do.releaseID}
@@ -604,6 +706,13 @@ func (l *Leg) runLayer(ctx context.Context, runID, layer string, vmid int, trigg
 		}
 	case layer == LayerDocker:
 		plan["select"] = "pending-docker" // ring 0: the wrapper checks the box's ROOT-OWNED ring-0 mark itself
+	case layer == LayerPVE && do.signed != nil:
+		plan["packages"], plan["signed"] = do.packages, do.signed
+		for _, p := range do.packages {
+			planned[p.Name] = true
+		}
+	case layer == LayerPVE:
+		plan["select"] = "pending-pve" // ring 0: the same root-owned mark; the wrapper picks installed Proxmox userspace
 	case !blk.Enabled:
 		plan["mode"] = "inventory"
 		lg.Info("osupdate: switched OFF for this box — reporting only")
@@ -637,6 +746,7 @@ func (l *Leg) runLayer(ctx context.Context, runID, layer string, vmid int, trigg
 	rep.Upgraded, rep.PassSeconds = wr.Upgraded, wr.PassSeconds
 	rep.DockerEngine, rep.Authority, rep.Undo = wr.DockerEngine, wr.Authority, wr.Undo
 	rep.OOMCheck = rawOrNil(wr.OOMCheck)
+	rep.PVEManager = wr.PVEManager
 	if rep.Outcome == "" {
 		switch {
 		case rep.Mode == "inventory" && !blk.Enabled:
@@ -654,21 +764,27 @@ func (l *Leg) runLayer(ctx context.Context, runID, layer string, vmid int, trigg
 	}
 	// Health: compare with the start of the pass; give restarted services time (only after an install).
 	cur := wr.HealthAfter
-	wantEngine := ""
+	wantEngine, wantPVE := "", ""
 	for _, u := range wr.Upgraded {
 		if u.Name == "docker-ce" {
 			wantEngine = EngineOf(u.Version)
 		}
+		if u.Name == "pve-manager" {
+			wantPVE = u.Version
+		}
 	}
 	verdict := func(h *Health) (bool, string) {
 		if layer == LayerDocker {
 			return DockerHealthVerdict(wr.HealthBefore, h, wantEngine, wr.DockerEngine)
 		}
-		if layer == LayerHost {
+		if layer == LayerHost || layer == LayerPVE {
 			t := hub.TunnelUnknown
 			if l.Tunnel != nil {
 				t, _ = l.Tunnel.Status(ctx)
 			}
+			if layer == LayerPVE {
+				return PVEHealthVerdict(wr.HealthBefore, h, t, wantPVE, wr.PVEManager)
+			}
 			return HostHealthVerdict(wr.HealthBefore, h, t)
 		}
 		return HealthVerdict(wr.HealthBefore, h)
@@ -708,6 +824,10 @@ func (l *Leg) runLayer(ctx context.Context, runID, layer string, vmid int, trigg
 		// the docker report carries the engine set only (the guest report already carries the Debian packages)
 		rep.Installed, rep.Pending = onlyDocker(wr.Installed), onlyDockerPending(wr.Pending)
 		rep.NotCovered = nil
+	} else if layer == LayerPVE {
+		// the pve report carries the Proxmox userspace set only — the hub's candidate is built from it
+		rep.Installed, rep.Pending = onlyPVE(wr.Installed), onlyPVEPending(wr.Pending)
+		rep.NotCovered = nil
 	} else {
 		rep.NotCovered = notCovered(wr.Pending, blk.Ring, planned)
 	}
@@ -732,6 +852,33 @@ func onlyDocker(in []Package) []Package {
 	return out
 }
 
+// onlyPVE keeps the installed Proxmox-origin packages the pve lane may touch (never a kernel / boot / firmware name).
+func onlyPVE(in []Package) []Package {
+	var out []Package
+	for _, p := range in {
+		if (p.Origin == InstalledPVEOrigin || p.Origin == PVEOrigin) && !hostSlowRE.MatchString(p.Name) && !DockerNames[p.Name] {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+func onlyPVEPending(in []Pending) []Pending {
+	var out []Pending
+	for _, p := range in {
+		if p.From == "" || hostSlowRE.MatchString(p.Name) || DockerNames[p.Name] {
+			continue
+		}
+		for _, o := range p.Origin {
+			if o == PVEOrigin {
+				out = append(out, p)
+				break
+			}
+		}
+	}
+	return out
+}
+
 func onlyDockerPending(in []Pending) []Pending {
 	var out []Pending
 	for _, p := range in {

internal/osupdate/leg_test.go

@@ -13,16 +13,19 @@ import (
 	"time"
 
 	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/pvegate"
 )
 
 // fakeWrapper plays /usr/local/sbin/felhom-os-apply: it reads the plan the leg wrote and answers per layer and mode.
 type fakeWrapper struct {
-	t         *testing.T
+	t           *testing.T
-	pending   []Pending
+	pending     []Pending
-	applyRep  map[string]WrapperReport // per layer
+	applyRep    map[string]WrapperReport // per layer
-	healthSeq map[string][]*Health     // per layer: answers to successive "health" calls
+	healthSeq   map[string][]*Health     // per layer: answers to successive "health" calls
-	plans     []map[string]any
+	plans       []map[string]any
-	keep      bool // R-868: like the real wrapper, keep an apply report beside the plan
+	keep        bool // R-868: like the real wrapper, keep an apply report beside the plan
+	pveGateHeld bool
+	kernelRep   map[string][]WrapperReport // R-836: per kernel-layer mode, successive answers (the last one repeats)
 }
 
 func yes() *bool { b := true; return &b }
@@ -50,9 +53,22 @@ func (f *fakeWrapper) Run(_ context.Context, name string, args ...string) ([]byt
 	f.plans = append(f.plans, plan)
 	layer := plan["layer"].(string)
 	ok := guestOK()
-	if layer == LayerHost {
+	if layer == LayerHost || layer == LayerPVE || layer == LayerKernel {
 		ok = hostOK()
 	}
+	if layer == LayerKernel {
+		if seq := f.kernelRep[plan["mode"].(string)]; len(seq) > 0 {
+			rep := seq[0]
+			if len(seq) > 1 {
+				f.kernelRep[plan["mode"].(string)] = seq[1:]
+			}
+			out, _ := json.Marshal(rep)
+			return []byte("OSAPPLY-REPORT " + string(out) + "\n"), []byte("os-apply: DONE rc=0\n"), nil
+		}
+	}
+	if layer == LayerPVE && plan["mode"] == "apply" {
+		f.pveGateHeld = pvegate.Stepping() // R-812: the /etc/pve write gate must be held while the pve step runs
+	}
 	var rep WrapperReport
 	switch plan["mode"] {
 	case "inventory":
@@ -160,8 +176,8 @@ func TestRing0_OneCallPerLayer(t *testing.T) {
 	if g.Outcome != "applied" || !g.Healthy || ho.Outcome != "applied" || !ho.Healthy {
 		t.Fatalf("guest %+v\nhost %+v", g, ho)
 	}
-	if calls(w) != "guest:apply,host:apply,guest:live-restore-on,docker:apply" {
+	if calls(w) != "guest:apply,host:apply,guest:live-restore-on,docker:apply,pve:apply" {
-		t.Fatalf("calls = %s, want one apply per layer, guest first, then live-restore and the ring-0 docker step", calls(w))
+		t.Fatalf("calls = %s, want one apply per layer, guest first, then live-restore, the ring-0 docker step and the pve step", calls(w))
 	}
 	for _, p := range w.plans[:2] {
 		if p["select"] != "pending-fast" || p["snapshot"] != "" || len(p["packages"].([]any)) != 0 {
@@ -171,7 +187,7 @@ func TestRing0_OneCallPerLayer(t *testing.T) {
 	if len(g.NotCovered) != 1 || g.NotCovered[0] != "docker-ce" {
 		t.Fatalf("not covered = %v", g.NotCovered)
 	}
-	if len(h.reports) != 3 || h.reports[0].Layer != LayerGuest || h.reports[1].Layer != LayerHost || h.reports[2].Layer != LayerDocker {
+	if len(h.reports) != 4 || h.reports[0].Layer != LayerGuest || h.reports[1].Layer != LayerHost || h.reports[2].Layer != LayerDocker || h.reports[3].Layer != LayerPVE {
 		t.Fatalf("hub got %+v", h.reports)
 	}
 }
@@ -389,7 +405,7 @@ func TestHostReport_CarriesRebootScanned(t *testing.T) {
 	}}
 	l, h := newLeg(t, w, &hub.WireOSUpdate{Ring: 0, Enabled: true})
 	run2(l, "night")
-	if len(h.reports) != 3 || !h.reports[1].RebootScanned || !h.reports[1].RebootNeeded || h.reports[0].RebootScanned {
+	if len(h.reports) != 4 || !h.reports[1].RebootScanned || !h.reports[1].RebootNeeded || h.reports[0].RebootScanned {
 		t.Fatalf("hub got %+v", h.reports)
 	}
 }
@@ -436,7 +452,12 @@ func TestDocker_Ring0PlanAndReport(t *testing.T) {
 		DockerEngine: "29.8.2", Authority: "ring0"}}}
 	l, _ := newLeg(t, w, &hub.WireOSUpdate{Ring: 0, Enabled: true})
 	p := l.Run(context.Background(), 9201, "night")
-	dp := w.plans[len(w.plans)-1]
+	var dp map[string]any
+	for _, x := range w.plans {
+		if x["layer"] == "docker" {
+			dp = x
+		}
+	}
 	if dp["layer"] != "docker" || dp["lane"] != "slow" || dp["select"] != "pending-docker" {
 		t.Fatalf("docker plan = %v", dp)
 	}

internal/osupdate/pve_test.go

@@ -0,0 +1,152 @@
+package osupdate
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/pvegate"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/reconcile"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
+)
+
+// ---- the Proxmox package step (R-812 option A, `09` §3 decision 163, `11` §5.10) ----
+
+// Ring 0: after a healthy host step the leg runs the pve layer — slow lane, select pending-pve — while holding the
+// /etc/pve write gate; the report carries only Proxmox userspace packages and pve-manager's version.
+//
+// COMPANION RED-PROOF (observed): call runLayer instead of runPVE in Run → "the /etc/pve write gate was not held".
+func TestPVE_Ring0PlanGateAndReport(t *testing.T) {
+	w := &fakeWrapper{t: t, applyRep: map[string]WrapperReport{LayerPVE: {
+		Upgraded: []Package{{Name: "pve-manager", Version: "9.2.21"}},
+		Installed: []Package{{Name: "pve-manager", Version: "9.2.21", Origin: "Proxmox"},
+			{Name: "proxmox-kernel-helper", Version: "9.0.4", Origin: "Proxmox"}, {Name: "libc6", Version: "u4", Origin: "Debian"}},
+		Pending: []Pending{{Name: "qemu-server", From: "9.0.1", To: "9.0.9", Origin: []string{PVEOrigin}},
+			{Name: "proxmox-kernel-7.0", From: "7.0.2", To: "7.0.14", Origin: []string{PVEOrigin}},
+			{Name: "libc6", From: "u3", To: "u4", Origin: []string{"Debian"}}},
+		PVEManager: "9.2.21", Authority: "ring0"}}}
+	l, h := newLeg(t, w, &hub.WireOSUpdate{Ring: 0, Enabled: true})
+	p := l.Run(context.Background(), 9201, "night")
+	var pp map[string]any
+	for _, x := range w.plans {
+		if x["layer"] == LayerPVE {
+			pp = x
+		}
+	}
+	if pp == nil || pp["lane"] != "slow" || pp["select"] != "pending-pve" {
+		t.Fatalf("pve plan = %v (calls %s)", pp, calls(w))
+	}
+	if !w.pveGateHeld {
+		t.Fatal("the /etc/pve write gate was not held while the pve step ran")
+	}
+	if pvegate.Stepping() {
+		t.Fatal("the gate must be released after the step")
+	}
+	r := p.PVE
+	if r.Outcome != "applied" || !r.Healthy || r.PVEManager != "9.2.21" {
+		t.Fatalf("pve report = %+v", r)
+	}
+	if len(r.Installed) != 1 || r.Installed[0].Name != "pve-manager" || len(r.Pending) != 1 || r.Pending[0].Name != "qemu-server" {
+		t.Fatalf("the pve report must carry Proxmox userspace only: installed=%v pending=%v", r.Installed, r.Pending)
+	}
+	if h.reports[len(h.reports)-1].Layer != LayerPVE {
+		t.Fatalf("the hub must get the pve report: %+v", h.reports)
+	}
+}
+
+// Ring 1 never takes a Proxmox step in the night leg.
+func TestPVE_Ring1NightLegNeverSteps(t *testing.T) {
+	w := &fakeWrapper{t: t}
+	l, _ := newLeg(t, w, &hub.WireOSUpdate{Ring: 1, Enabled: true})
+	if p := l.Run(context.Background(), 9201, "night"); p.PVE.Layer != "" || strings.Contains(calls(w), "pve") {
+		t.Fatalf("ring 1 took a pve step: %s", calls(w))
+	}
+}
+
+// No healthy host step (a BYO box, or an unhealthy host step) → no pve step.
+func TestPVE_SkippedWithoutAHealthyHostStep(t *testing.T) {
+	w := &fakeWrapper{t: t}
+	l, _ := newLeg(t, w, &hub.WireOSUpdate{Ring: 0, Enabled: true})
+	l.Appliance = false
+	if p := l.Run(context.Background(), 9201, "night"); p.PVE.Layer != "" || strings.Contains(calls(w), "pve") {
+		t.Fatalf("a BYO box took a pve step: %s", calls(w))
+	}
+	w2 := &fakeWrapper{t: t}
+	l2, _ := newLeg(t, w2, &hub.WireOSUpdate{Ring: 0, Enabled: true})
+	l2.Tunnel = fakeTunnel{"stopped"} // the host step reads unhealthy
+	w2.applyRep = map[string]WrapperReport{LayerHost: {Upgraded: []Package{{Name: "libc6", Version: "u4"}}}}
+	if p := l2.Run(context.Background(), 9201, "night"); p.PVE.Layer != "" || strings.Contains(calls(w2), "pve") {
+		t.Fatalf("a pve step ran after an unhealthy host step: %s", calls(w2))
+	}
+}
+
+// A write in flight that never finishes makes the pve step give up (failed), never run without the gate.
+func TestPVE_GivesUpWhenAWriteDoesNotFinish(t *testing.T) {
+	old := pveDrainWait
+	pveDrainWait = 50_000_000 // 50 ms
+	defer func() { pveDrainWait = old }()
+	rel, _, _ := pvegate.Write(context.Background())
+	defer rel()
+	w := &fakeWrapper{t: t}
+	l, _ := newLeg(t, w, &hub.WireOSUpdate{Ring: 0, Enabled: true})
+	p := l.Run(context.Background(), 9201, "night")
+	if p.PVE.Outcome != "failed" || strings.Contains(calls(w), "pve") {
+		t.Fatalf("the pve step must fail without a wrapper call: %+v calls=%s", p.PVE, calls(w))
+	}
+}
+
+// THE pve health rule. COMPANION RED-PROOF (observed): drop the container-id loop or the pve-manager check in
+// PVEHealthVerdict → the matching case below fails.
+func TestPVEHealthVerdict(t *testing.T) {
+	before, after := hostOK(), hostOK()
+	before.Guest.Containers["app"] = Container{State: "running", Health: "healthy", ID: "a1"}
+	after.Guest.Containers["app"] = Container{State: "running", Health: "healthy", ID: "a1"}
+	if ok, why := PVEHealthVerdict(before, after, hub.TunnelRunning, "9.2.21", "9.2.21"); !ok {
+		t.Fatalf("healthy step read unhealthy: %s", why)
+	}
+	if ok, _ := PVEHealthVerdict(before, after, hub.TunnelRunning, "9.2.21", "9.2.2"); ok {
+		t.Fatal("pveversion still on the old pve-manager must fail")
+	}
+	after.Guest.Containers["app"] = Container{State: "running", Health: "healthy", ID: "b2"}
+	if ok, why := PVEHealthVerdict(before, after, hub.TunnelRunning, "", "9.2.2"); ok || !strings.Contains(why, "id changed") {
+		t.Fatalf("an app restarted by the Proxmox step must fail, got ok=%v %q", ok, why)
+	}
+}
+
+// The signed executor hands the RAW envelope and the exact list to the wrapper's pve layer.
+func TestPVEStepExecutor_PassesTheSignedEnvelope(t *testing.T) {
+	w := &fakeWrapper{t: t, applyRep: map[string]WrapperReport{LayerPVE: {
+		Upgraded: []Package{{Name: "pve-manager", Version: "9.2.21"}}, PVEManager: "9.2.21", Authority: "signed"}}}
+	l, h := newLeg(t, w, &hub.WireOSUpdate{Ring: 1, Enabled: true})
+	e := PVEStepExecutor{Leg: l, Guest: func(context.Context) (int, error) { return 9201, nil }}
+	params, _ := json.Marshal(PVEStepParams{ReleaseID: "os-pve-1", Packages: []Package{{Name: "pve-manager", Version: "9.2.21", Origin: PVEOrigin}}})
+	ctx := signedjobs.WithSignedOp(context.Background(), &reconcile.SignedOp{Blob: []byte(`{"op":"os_pve_step"}`), Sig: []byte("SIG")})
+	if err := e.Execute(ctx, OpPVEStep, params); err != nil {
+		t.Fatal(err)
+	}
+	pp := w.plans[len(w.plans)-1]
+	sg, _ := pp["signed"].(map[string]any)
+	if pp["layer"] != LayerPVE || pp["lane"] != "slow" || pp["release_id"] != "os-pve-1" || sg == nil ||
+		sg["blob_b64"] != base64.StdEncoding.EncodeToString([]byte(`{"op":"os_pve_step"}`)) || sg["sig"] != "SIG" {
+		t.Fatalf("pve plan = %v", pp)
+	}
+	if !w.pveGateHeld || calls(w) != "pve:apply" || len(h.reports) != 1 || h.reports[0].Trigger != "signed" {
+		t.Fatalf("gate=%v calls=%s reports=%+v", w.pveGateHeld, calls(w), h.reports)
+	}
+	if err := e.Execute(context.Background(), OpPVEStep, params); err == nil {
+		t.Fatal("no envelope must refuse")
+	}
+	if err := e.Execute(context.Background(), OpDockerStep, params); err != signedjobs.ErrNoExecutor {
+		t.Fatalf("another op must pass through the chain: %v", err)
+	}
+}
+
+// os_pve_step is never benign.
+func TestPVEStep_IsDestructiveClass(t *testing.T) {
+	if reconcile.Classify(reconcile.ClassOSPVEStep, reconcile.Provenance{}) != reconcile.Destructive {
+		t.Fatal("os_pve_step must be destructive-class (signed, operational key)")
+	}
+}

internal/osupdate/pvejob.go

@@ -0,0 +1,85 @@
+package osupdate
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
+)
+
+// OpPVEStep is the signed op class of a Proxmox package step (R-812 option A, `11` §5.10): a ring-1 box takes an
+// approved Proxmox set only through it. No undo in this release. CC may sign it until the first paying customer.
+const OpPVEStep = "os_pve_step"
+
+// PVEStepParams are the signed params. The wrapper compares Packages with the plan byte-for-byte.
+type PVEStepParams struct {
+	ReleaseID string    `json:"release_id"`
+	Packages  []Package `json:"packages"`
+	VMID      int       `json:"vmid,omitempty"`
+}
+
+// PVEStepExecutor runs a verified os_pve_step (signedjobs.Executor) under the host-wide heavy-op gate (Gate) and the
+// /etc/pve write gate (inside runPVE).
+type PVEStepExecutor struct {
+	Leg   *Leg
+	Guest func(ctx context.Context) (int, error)
+	Gate  func(ctx context.Context) (release func(), err error)
+}
+
+// Execute implements signedjobs.Executor.
+func (e PVEStepExecutor) Execute(ctx context.Context, op string, params json.RawMessage) error {
+	if op != OpPVEStep {
+		return signedjobs.ErrNoExecutor
+	}
+	so, ok := signedjobs.SignedOpFrom(ctx)
+	if !ok {
+		return fmt.Errorf("os_pve_step: no signed envelope in the context — the wrapper could not verify it")
+	}
+	var p PVEStepParams
+	if err := json.Unmarshal(params, &p); err != nil || len(p.Packages) == 0 {
+		return fmt.Errorf("os_pve_step: params must name the Proxmox set: %v", err)
+	}
+	vmid := p.VMID
+	if vmid == 0 {
+		if e.Guest == nil {
+			return fmt.Errorf("os_pve_step: no vmid and no guest finder")
+		}
+		v, err := e.Guest(ctx)
+		if err != nil {
+			return fmt.Errorf("os_pve_step: find the customer guest: %w", err)
+		}
+		vmid = v
+	}
+	if e.Gate != nil {
+		release, err := e.Gate(ctx)
+		if err != nil {
+			return fmt.Errorf("os_pve_step: heavy-op gate busy (a backup or restore-test runs): %w", err)
+		}
+		defer release()
+	}
+	rep := e.Leg.RunPVESigned(ctx, vmid, p, so.Blob, string(so.Sig))
+	switch rep.Outcome {
+	case "applied", "nothing":
+		if rep.Healthy {
+			return nil
+		}
+	}
+	return fmt.Errorf("os_pve_step: %s (%s) %s", rep.Outcome, rep.HealthReason, string(rep.Refused))
+}
+
+// RunPVESigned is one signed Proxmox step (ring 1): the pve layer with the signed envelope, which the wrapper verifies
+// itself, holding the /etc/pve write gate.
+func (l *Leg) RunPVESigned(ctx context.Context, vmid int, p PVEStepParams, blob []byte, sig string) Report {
+	unlock := l.lockPass(true)
+	defer unlock()
+	l.sendUnsentLocked(ctx) // R-868
+	runID := l.now().UTC().Format("20060102T150405Z")
+	rid := p.ReleaseID
+	if rid == "" {
+		rid = "signed-" + runID
+	}
+	return l.runPVE(ctx, runID, vmid, "signed", l.Block(), dockerOpts{releaseID: rid, packages: p.Packages,
+		signed: map[string]string{"blob_b64": base64.StdEncoding.EncodeToString(blob), "sig": sig}})
+}

internal/osupdate/r899_ring_test.go

@@ -0,0 +1,32 @@
+package osupdate
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+)
+
+// After a boot the agent has not fetched the hub's block yet; the after-boot kernel report must still carry the
+// box's real ring (seen 2026-10-08: a ring-0 box's „judging" report said ring 1). Red-proof: return Block().Ring
+// from kernelReportRing and the saved-block case fails with 1.
+func TestKernelReportRing_BeforeFirstFetch(t *testing.T) {
+	dir := t.TempDir()
+	l := &Leg{PlanDir: dir}
+	if got := l.kernelReportRing(); got != 1 {
+		t.Fatalf("nothing fetched, nothing saved: ring %d, want 1 (the old default)", got)
+	}
+	l.saveBlock(&hub.WireOSUpdate{Ring: 0, Enabled: true})
+	l2 := &Leg{PlanDir: dir} // a fresh daemon after the reboot: no block fetched yet
+	if got := l2.kernelReportRing(); got != 0 {
+		t.Fatalf("ring-0 block saved before the reboot: ring %d, want 0", got)
+	}
+	l2.SetBlock(&hub.WireOSUpdate{Ring: 1, Enabled: true})
+	if got := l2.kernelReportRing(); got != 1 {
+		t.Fatalf("a fetched block wins over the saved one: ring %d, want 1", got)
+	}
+	if _, err := os.Stat(filepath.Join(dir, SavedBlockFile)); err != nil {
+		t.Fatalf("saved block missing: %v", err)
+	}
+}

internal/osupdate/unsent.go

@@ -142,24 +142,42 @@ func (l *Leg) reportFromKept(ctx context.Context, wr WrapperReport, path string)
 	default:
 		rep.Outcome = "applied"
 	}
+	if wr.Layer == LayerKernel {
+		// a kernel STAGE changes nothing the box runs (the new kernel only boots once, at the night's reboot), so its
+		// kept copy needs no fresh health reading (R-836)
+		rep.Kernel = rawOrNil(wr.Kernel)
+		rep.Upgraded, rep.PassSeconds, rep.Authority = wr.Upgraded, wr.PassSeconds, wr.Authority
+		if rep.Outcome == "applied" {
+			rep.Outcome = "staged"
+		}
+		rep.Healthy, rep.HealthReason = rep.Outcome == "staged" || rep.Outcome == "nothing", prefix
+		return rep
+	}
 	rep.Upgraded, rep.PassSeconds = wr.Upgraded, wr.PassSeconds
 	rep.DockerEngine, rep.Authority, rep.Undo = wr.DockerEngine, wr.Authority, wr.Undo
 	rep.OOMCheck = rawOrNil(wr.OOMCheck)
-	wantEngine := ""
+	rep.PVEManager = wr.PVEManager
+	wantEngine, wantPVE := "", ""
 	for _, u := range wr.Upgraded {
 		if u.Name == "docker-ce" {
 			wantEngine = EngineOf(u.Version)
 		}
+		if u.Name == "pve-manager" {
+			wantPVE = u.Version
+		}
 	}
 	verdict := func(h *Health) (bool, string) {
 		switch wr.Layer {
 		case LayerDocker:
 			return DockerHealthVerdict(wr.HealthBefore, h, wantEngine, wr.DockerEngine)
-		case LayerHost:
+		case LayerHost, LayerPVE:
 			t := hub.TunnelUnknown
 			if l.Tunnel != nil {
 				t, _ = l.Tunnel.Status(ctx)
 			}
+			if wr.Layer == LayerPVE {
+				return PVEHealthVerdict(wr.HealthBefore, h, t, wantPVE, wr.PVEManager)
+			}
 			return HostHealthVerdict(wr.HealthBefore, h, t)
 		}
 		return HealthVerdict(wr.HealthBefore, h)
@@ -167,7 +185,7 @@ func (l *Leg) reportFromKept(ctx context.Context, wr WrapperReport, path string)
 	ok, why := verdict(wr.HealthAfter)
 	if !ok && len(wr.Upgraded) > 0 && wr.VMID > 0 {
 		lane := "fast"
-		if wr.Layer == LayerDocker {
+		if wr.Layer == LayerDocker || wr.Layer == LayerPVE {
 			lane = "slow"
 		}
 		if hr, err := l.call(ctx, "kept-"+runID, map[string]any{"release_id": "kept", "layer": wr.Layer, "lane": lane,
@@ -187,6 +205,8 @@ func (l *Leg) reportFromKept(ctx context.Context, wr WrapperReport, path string)
 	rep.RebootScanned = wr.RebootScanned
 	if wr.Layer == LayerDocker {
 		rep.Installed, rep.Pending = onlyDocker(wr.Installed), onlyDockerPending(wr.Pending)
+	} else if wr.Layer == LayerPVE {
+		rep.Installed, rep.Pending = onlyPVE(wr.Installed), onlyPVEPending(wr.Pending)
 	} else {
 		planned := map[string]bool{}
 		for _, u := range wr.Upgraded {

internal/proxmox/client.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/pvegate"
 	"io"
 	"net/http"
 	"net/url"
@@ -105,6 +106,15 @@ func (c *Client) do(ctx context.Context, method, path string, body io.Reader, ou
 // doBody is the single HTTP chokepoint: builds the request, sets auth, executes,
 // maps non-2xx to APIError, and decodes the data envelope.
 func (c *Client) doBody(ctx context.Context, method, path string, body io.Reader, contentType string, out any) error {
+	// R-812 option A: every non-GET call may write /etc/pve — it waits while a Proxmox package step restarts pmxcfs
+	// (pvegate). Pinned by TestPVEGate_ClientWriteWaitsGetDoesNot.
+	if method != http.MethodGet {
+		release, _, gerr := pvegate.Write(ctx)
+		if gerr != nil {
+			return fmt.Errorf("proxmox: %s %s held back by a Proxmox package step: %w", method, path, gerr)
+		}
+		defer release()
+	}
 	req, err := http.NewRequestWithContext(ctx, method, c.base+path, body)
 	if err != nil {
 		return fmt.Errorf("proxmox: building request: %w", err)

internal/proxmox/privileged.go

@@ -4,8 +4,10 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"gitea.dooplex.hu/admin/felhom-agent/internal/pvegate"
 	"io"
 	"os/exec"
+	"path/filepath"
 	"strconv"
 )
 
@@ -59,6 +61,15 @@ func (r *ExecRunner) Run(ctx context.Context, name string, args ...string) ([]by
 // RunStdin is Run with the process stdin fed from stdin (nil = no stdin). The sudo-prefix/mode
 // handling is identical to Run — kept here so both paths share one place.
 func (r *ExecRunner) RunStdin(ctx context.Context, stdin io.Reader, name string, args ...string) ([]byte, []byte, error) {
+	// R-812 option A: a root CLI that writes /etc/pve waits while a Proxmox package step runs (pvegate).
+	// Pinned by TestPVEGate_ExecRunnerPctSetWaits / TestWritesEtcPVE.
+	if WritesEtcPVE(name, args) {
+		release, _, gerr := pvegate.Write(ctx)
+		if gerr != nil {
+			return nil, nil, fmt.Errorf("proxmox: %s held back by a Proxmox package step: %w", name, gerr)
+		}
+		defer release()
+	}
 	var cmd *exec.Cmd
 	if r.Mode == RunnerSudo {
 		sudo := r.SudoPath
@@ -77,6 +88,28 @@ func (r *ExecRunner) RunStdin(ctx context.Context, stdin io.Reader, name string,
 	return stdout.b, stderr.b, err
 }
 
+// WritesEtcPVE reports whether a root command writes /etc/pve: `pct` with a config-changing verb, `pvesm`, `pveum`,
+// and the PBS storage wrapper's create / reconcile verbs. `pct exec|status|list|config` and every other command do not
+// (the os-update wrapper itself must never wait on the gate its own step holds). Pinned by TestWritesEtcPVE.
+func WritesEtcPVE(name string, args []string) bool {
+	base := filepath.Base(name)
+	switch base {
+	case "pvesm", "pveum":
+		return true
+	case "pct":
+		if len(args) == 0 {
+			return false
+		}
+		switch args[0] {
+		case "set", "create", "destroy", "restore", "unlock", "resize", "snapshot", "delsnapshot", "rollback", "move-volume", "start", "stop", "reboot", "shutdown":
+			return true
+		}
+	case "felhom-pbs-apply":
+		return len(args) > 0 && (args[0] == "create" || args[0] == "reconcile")
+	}
+	return false
+}
+
 // Privileged is the root-CLI backend.
 type Privileged struct {
 	runner Runner

internal/proxmox/pvegate_test.go

@@ -0,0 +1,92 @@
+package proxmox
+
+import (
+	"context"
+	"net/http"
+	"testing"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/pvegate"
+)
+
+// R-812 option A: while a Proxmox package step holds the gate, a non-GET API call waits and a GET does not.
+//
+// COMPANION RED-PROOF (observed): delete the pvegate.Write block in doBody → this fails with "a PUT reached the API
+// while the Proxmox step held the gate". Restored. (audits/day-2026-10-07/B/red-pvegate-chokepoints.txt)
+func TestPVEGate_ClientWriteWaitsGetDoesNot(t *testing.T) {
+	d := &mockDoer{fn: func(*http.Request) (*http.Response, error) { return jsonResp(200, `{"data":null}`), nil }}
+	c := newTestClient(d)
+	end, err := pvegate.Step(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := c.get(context.Background(), "/nodes", nil); err != nil {
+		t.Fatalf("a GET must not wait on the gate: %v", err)
+	}
+	if d.calls != 1 {
+		t.Fatalf("the GET must reach the API, calls=%d", d.calls)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+	err = c.postForm(ctx, http.MethodPut, "/nodes/x/lxc/9201/config", nil, nil)
+	if d.calls != 1 {
+		end()
+		t.Fatal("a PUT reached the API while the Proxmox step held the gate")
+	}
+	if err == nil {
+		end()
+		t.Fatal("a PUT held back past its deadline must fail")
+	}
+	end()
+	if err := c.postForm(context.Background(), http.MethodPut, "/nodes/x/lxc/9201/config", nil, nil); err != nil || d.calls != 2 {
+		t.Fatalf("after the step the PUT must go through (err=%v calls=%d)", err, d.calls)
+	}
+}
+
+// A root `pct set` waits on the gate; `pct exec` does not.
+//
+// COMPANION RED-PROOF (observed): delete the WritesEtcPVE block in RunStdin → this fails with "pct set ran while the
+// Proxmox step held the gate". Restored.
+func TestPVEGate_ExecRunnerPctSetWaits(t *testing.T) {
+	r := &ExecRunner{Mode: RunnerDirect}
+	end, err := pvegate.Step(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer end()
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+	start := time.Now()
+	_, _, err = r.Run(ctx, "/nonexistent/pct", "set", "9201", "-mp8", "/x")
+	if err == nil || time.Since(start) < 90*time.Millisecond {
+		t.Fatalf("pct set ran while the Proxmox step held the gate (err=%v after %s)", err, time.Since(start))
+	}
+	start = time.Now()
+	_, _, _ = r.Run(context.Background(), "/nonexistent/pct", "exec", "9201", "--", "true")
+	if time.Since(start) > 80*time.Millisecond {
+		t.Fatal("pct exec must not wait on the gate")
+	}
+}
+
+func TestWritesEtcPVE(t *testing.T) {
+	for _, c := range []struct {
+		name string
+		args []string
+		want bool
+	}{
+		{"pct", []string{"set", "9201", "-mp8", "x"}, true},
+		{"/usr/sbin/pct", []string{"create", "9201"}, true},
+		{"pct", []string{"exec", "9201", "--", "true"}, false},
+		{"pct", []string{"status", "9201"}, false},
+		{"pvesm", []string{"add", "dir", "x"}, true},
+		{"pveum", []string{"acl", "modify"}, true},
+		{"/usr/local/sbin/felhom-pbs-apply", []string{"reconcile"}, true},
+		{"/usr/local/sbin/felhom-pbs-apply", []string{"read"}, false},
+		{"/usr/local/sbin/felhom-os-apply", []string{"--plan", "x"}, false},
+		{"pct", nil, false},
+	} {
+		if got := WritesEtcPVE(c.name, c.args); got != c.want {
+			t.Errorf("WritesEtcPVE(%s %v) = %v, want %v", c.name, c.args, got, c.want)
+		}
+	}
+}

internal/pvegate/pvegate.go

@@ -0,0 +1,104 @@
+// Package pvegate keeps the agent's own writes to /etc/pve out of the way of a Proxmox package step (R-812 option A,
+// `09` §3 decision 163, `11` §5.10).
+//
+// WHY. A `pve` step upgrades pve-cluster / pve-manager / qemu-server / pve-container; their postinst scripts restart
+// pmxcfs (the FUSE filesystem behind /etc/pve) and the API daemons. A write that lands while pmxcfs restarts fails or,
+// worse, half-lands (design-R-812 §3 A, "can go wrong"). Backups and restore-tests are already kept out by the
+// host-wide heavy-op gate; this gate covers everything else the agent writes: every non-GET Proxmox API call
+// (proxmox.Client.doBody) and every root CLI that writes /etc/pve (proxmox.ExecRunner — `pct set|create|…`, `pvesm`,
+// `pveum`, `felhom-pbs-apply create|reconcile`).
+//
+// THE RULE. Write waits while a step runs (bounded by its own context). Step marks the step and then waits until every
+// write already in flight has finished; it never waits forever (its context bounds it, and the caller gives up and
+// does not run the step). One step at a time. Pinned by pvegate_test.go and, at the two chokepoints, by
+// proxmox TestPVEGate_*.
+package pvegate
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"time"
+)
+
+var (
+	mu       sync.Mutex
+	inFlight int
+	stepping bool
+	stepDone chan struct{}
+)
+
+// ErrStepRunning is returned by Step when another step already holds the gate.
+var ErrStepRunning = errors.New("pvegate: a Proxmox package step is already running")
+
+// Write marks one /etc/pve write in flight, first waiting while a Proxmox package step runs. The returned release must
+// be called when the write has finished. waited reports how long the write was held back.
+func Write(ctx context.Context) (release func(), waited time.Duration, err error) {
+	start := time.Now()
+	for {
+		mu.Lock()
+		if !stepping {
+			inFlight++
+			mu.Unlock()
+			var once sync.Once
+			return func() {
+				once.Do(func() {
+					mu.Lock()
+					inFlight--
+					mu.Unlock()
+				})
+			}, time.Since(start), nil
+		}
+		ch := stepDone
+		mu.Unlock()
+		select {
+		case <-ch:
+		case <-ctx.Done():
+			return nil, time.Since(start), ctx.Err()
+		}
+	}
+}
+
+// Step marks a Proxmox package step and waits until every /etc/pve write already in flight has finished. On error the
+// gate is released again and the step must not run. end releases the gate and lets the held-back writes go.
+func Step(ctx context.Context) (end func(), err error) {
+	mu.Lock()
+	if stepping {
+		mu.Unlock()
+		return nil, ErrStepRunning
+	}
+	stepping = true
+	done := make(chan struct{})
+	stepDone = done
+	mu.Unlock()
+	var once sync.Once
+	end = func() {
+		once.Do(func() {
+			mu.Lock()
+			stepping = false
+			close(done)
+			mu.Unlock()
+		})
+	}
+	for {
+		mu.Lock()
+		n := inFlight
+		mu.Unlock()
+		if n == 0 {
+			return end, nil
+		}
+		select {
+		case <-ctx.Done():
+			end()
+			return nil, ctx.Err()
+		case <-time.After(50 * time.Millisecond):
+		}
+	}
+}
+
+// Stepping reports whether a Proxmox package step holds the gate (for logs).
+func Stepping() bool {
+	mu.Lock()
+	defer mu.Unlock()
+	return stepping
+}

internal/pvegate/pvegate_test.go

@@ -0,0 +1,104 @@
+package pvegate
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+// A write that starts while a step runs waits until the step ends.
+//
+// COMPANION RED-PROOF (observed): make Write ignore `stepping` → this fails with "the write went through while the
+// Proxmox step held the gate". Restored. (audits/day-2026-10-07/B/red-pvegate.txt)
+func TestWrite_WaitsWhileAStepRuns(t *testing.T) {
+	end, err := Step(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	got := make(chan time.Time, 1)
+	go func() {
+		rel, _, err := Write(context.Background())
+		if err == nil {
+			rel()
+		}
+		got <- time.Now()
+	}()
+	select {
+	case <-got:
+		end()
+		t.Fatal("the write went through while the Proxmox step held the gate")
+	case <-time.After(150 * time.Millisecond):
+	}
+	ended := time.Now()
+	end()
+	select {
+	case at := <-got:
+		if at.Before(ended) {
+			t.Fatal("the write finished before the step ended")
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatal("the write never went through after the step ended")
+	}
+}
+
+// A step waits for a write already in flight before it starts.
+func TestStep_WaitsForAWriteInFlight(t *testing.T) {
+	rel, _, err := Write(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	started := make(chan struct{})
+	go func() {
+		end, err := Step(context.Background())
+		if err == nil {
+			close(started)
+			end()
+		}
+	}()
+	select {
+	case <-started:
+		rel()
+		t.Fatal("the step started while a write was in flight")
+	case <-time.After(150 * time.Millisecond):
+	}
+	rel()
+	select {
+	case <-started:
+	case <-time.After(2 * time.Second):
+		t.Fatal("the step never started after the write finished")
+	}
+}
+
+// A step that cannot drain the writes in time gives up and releases the gate (it never waits forever).
+func TestStep_GivesUpAndReleases(t *testing.T) {
+	rel, _, _ := Write(context.Background())
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+	if _, err := Step(ctx); err == nil {
+		t.Fatal("the step must give up while a write is in flight past its deadline")
+	}
+	if Stepping() {
+		t.Fatal("a step that gave up must release the gate")
+	}
+	rel()
+}
+
+// A write held back past its own deadline returns the context's error.
+func TestWrite_HonoursItsContext(t *testing.T) {
+	end, _ := Step(context.Background())
+	defer end()
+	ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
+	defer cancel()
+	if _, _, err := Write(ctx); err == nil {
+		t.Fatal("a write held back past its deadline must fail")
+	}
+}
+
+// One step at a time.
+func TestStep_OneAtATime(t *testing.T) {
+	end, _ := Step(context.Background())
+	defer end()
+	if _, err := Step(context.Background()); err != ErrStepRunning {
+		t.Fatalf("a second step must be refused, got %v", err)
+	}
+}

internal/reconcile/classify.go

@@ -52,6 +52,15 @@ const (
 	// (signed, operational key) like agent_update; the root wrapper re-verifies the same signature itself.
 	ClassOSDockerStep OpClass = "os_docker_step"
 
+	// A Proxmox package step on the host (R-812 option A, `11` §5.10) — ring 1. Destructive-class (signed, operational
+	// key) like os_docker_step; the root wrapper re-verifies the same signature itself.
+	ClassOSPVEStep OpClass = "os_pve_step"
+
+	// A kernel step on the host (R-836, `09` §3 decision 172, `11` §5.11) — ring 1: it STAGES a kernel (install + the
+	// one-shot flag; the night leg reboots it). Destructive-class (signed, operational key) like os_pve_step; the root
+	// wrapper re-verifies the same signature itself.
+	ClassOSKernelStep OpClass = "os_kernel_step"
+
 	// The config bundle (agent v0.143.0, R-840, `11` §5.4.2): the box's ROOT-OWNED files (sudoers, wrappers, units).
 	// Destructive-class (signed, operational key) like agent_update; the root wrapper re-verifies the signature itself.
 	ClassAgentConfigUpdate OpClass = "agent_config_update"
@@ -123,7 +132,7 @@ func Classify(class OpClass, prov Provenance) Disposition {
 		return Destructive
 	case ClassKeyRotation:
 		return Destructive
-	case ClassAgentUpdate, ClassOSDockerStep, ClassAgentConfigUpdate:
+	case ClassAgentUpdate, ClassOSDockerStep, ClassOSPVEStep, ClassOSKernelStep, ClassAgentConfigUpdate:
 		// Never benign — no agent-internal provenance can make replacing the agent binary
 		// unsigned-safe (a compromised process must not be able to self-bless an update).
 		return Destructive