Session Handoff [rv3028-eeprom]: meshcore-dev/MeshCore#3421 description now tracks liquidraver/ZephCore#106; boot-recovery facts sent to Zephyr #24

Next steps, in priority order

1. Sweep every upstream PR and issue authored by ptr727 (the commands are in link Session Handoff [rv3028-eeprom]: All upstream PRs answered; watch for maintainer review #18, step 1). Anything with updatedAt after 2026-10-08T14:34Z is new; the 14:33Z update on Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421 is our own description edit. Done means each maintainer comment is answered, or put to Pieter as a dialog.
2. #3421 is converged at 0f038054, and the RV3028 position stays FROZEN. Change code only if a maintainer requires it or a test fails, and park every other finding for Pieter. Any code change re-runs the full acceptance matrix A-H on the exact commit before it is pushed. After that, ask Pieter in a dialog to re-request Copilot in the web UI, with the URL.
3. When Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421 or #3545 merges, rebase the other. They conflict in AutoDiscoverRTCClock::begin(), though each merges cleanly onto dev.
   • Store RV3028 backup switchover and trickle charger config in EEPROM 🤖🤖 meshcore-dev/MeshCore#3545 still calls rtc_rv3028.set24HourMode() in begin(). That's Melopero's unchecked read-modify-write: a failed read writes FDh back to Control 2, RESET bit included. Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421 removed it on purpose, so the rebase must keep it removed.
   • If the rebase lands on Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421, re-run the matrix under step 2's rule.
4. The cross-project paragraphs are no longer shared word for word. Since ZephCore diverged on 2026-10-07, each project words its own paragraphs. Keep Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421's description of the other two projects accurate. Edit it only with Pieter's go, using fully qualified owner/repo#N references, and tell the peer session afterwards.
5. Parked for Pieter, not code:
   • RTClib's DS3231 now() ignores the 12-hour flag. Revisit after the RTC PRs land.
   • The two MeshCore bugs from link Session Handoff [rv3028-eeprom]: Two RTC PRs re-pushed with cross-firmware fixes; triage Copilot headlines #19, step 4, stay ON HOLD until the RTC PRs land.
   • New this round: in every MeshCore version, an RV3028 that doesn't ACK at boot is never probed again until a reboot. This came up while answering the Zephyr session; see step 6. No change under the freeze.
6. Cross-project boot-recovery rule (Pieter deciding). The Zephyr session is documenting Zephyr's init-failure behaviour (-ENODEV until reboot) in a draft issue on Pieter's Zephyr fork, issue 36. Pieter is weighing a "self-healing" rule for all three projects: config failures stay pending, and no time is taken or written until Control 2 reads back 24-hour with RESET=0. MeshCore's facts have been sent (see What the last round did). MeshCore acts only if Pieter adopts a rule that needs it.
7. Cleanup stays deferred ("Watch only"). Keep the hardware builds and worktrees until a PR merges or is declined.

External blockers

• MeshCore maintainers: review of Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421, Adopt an RTC only if its time registers read like that chip 🤖🤖 meshcore-dev/MeshCore#3544, Store RV3028 backup switchover and trickle charger config in EEPROM 🤖🤖 meshcore-dev/MeshCore#3545, Write and read the RX8130CE WEEK register as one-hot 🤖🤖 meshcore-dev/MeshCore#3550, Reject a negative sensor list start index 🤖🤖 meshcore-dev/MeshCore#3433 and Pass TELEM_RAK12500_ADDRESS to the RAK12500 I2C probe 🤖🤖 meshcore-dev/MeshCore#3434, plus Do not feed an invalid GPS time into the RTC 🤖🤖 meshcore-dev/MeshCore#3422, Make GPS status reporting say what was actually checked 🤖🤖 meshcore-dev/MeshCore#3423 and Treat the GPS enable pin as a pin number, not a truth value 🤖🤖 meshcore-dev/MeshCore#3425 (draft). Nothing is owed from our side.
• Copilot re-request: after any upstream push it still needs Pieter in the web UI. Ask in a dialog, with the PR URL and the "Reviewers" sidebar location.
• Pieter: whether there will be a cross-project boot-recovery rule (step 6).
• Counterparts: drivers: rtc: rv3028: reject time accesses cut short by a switchover zephyrproject-rtos/zephyr#121389 and drivers: rv3028: disable backup switchover during EEPROM access zephyrproject-rtos/zephyr#121252 wait on Zephyr reviewers. Each peer session owns its own.

Internal dependencies

• Step 3 waits on an upstream merge. The parked items in step 5 wait on the RTC PRs landing.
• A Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421 code change (step 2, or step 6 if Pieter adopts a rule) must finish its matrix run before step 3's rebase, so that only one matrix runs per pushed commit.

State

Re-derive all of this; it was true at 2026-10-08T15:00Z.

• Upstream dev is at 2dbd463e. Its AutoDiscoverRTCClock.cpp is unchanged since 3e3150c8, and all six fix branches still merge onto it cleanly.
• Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421 description:
  • Its cross-project paragraph links rtc: write the RTC time only for years 2000-2099 liquidraver/ZephCore#105 (which replaces rtc: write the RV3028 time with an A0h year mark, and only 2000-2099 liquidraver/ZephCore#103) and says that Zephyr and MeshCore share A0h, while ZephCore keeps its split write.
  • Its 12-hour paragraph was edited this round to describe rtc: clear the RV3028 12-hour bit at boot liquidraver/ZephCore#106 at db69172; the ZephCore session confirmed it.
  • The commit message's "all three adopted" line is stale. Pieter chose to leave it, since a force-push only for that isn't worth it.
• Counterparts:
  • ZephCore: rtc: write the RTC time only for years 2000-2099 liquidraver/ZephCore#105 (9b68b7e, split year write, 2000-2099) and rtc: clear the RV3028 12-hour bit at boot liquidraver/ZephCore#106 (db69172, 12-hour clear at boot; takes no time if the clear fails) are both MERGED. rtc: write the RV3028 time with an A0h year mark, and only 2000-2099 liquidraver/ZephCore#103 and rtc: select 24-hour mode before a time write, and take no time in 12-hour mode liquidraver/ZephCore#104 are closed.
  • Zephyr: drivers: rtc: rv3028: reject time accesses cut short by a switchover zephyrproject-rtos/zephyr#121389 is at 82e160257cc and drivers: rv3028: disable backup switchover during EEPROM access zephyrproject-rtos/zephyr#121252 at 751beb04cba, both open.
• Hardware: unchanged since link Session Handoff [rv3028-eeprom]: MeshCore #3421 converged at 0f038054 after an all-PASS acceptance matrix; RV3028 position frozen #23. The test board runs the acceptance build local/hw-accept (src/ identical to 0f038054).
• Worktrees: same as link Session Handoff [rv3028-eeprom]: MeshCore #3421 converged at 0f038054 after an all-PASS acceptance matrix; RV3028 position frozen #23. The primary checkout is clean on main.

The parked decision queue

0 parked: the fork has no open decision issue. This round's one decision (edit the meshcore-dev#3421 sentence) was asked as a dialog and answered.

What the last round did

• Edited the Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421 description (Pieter: "Edit sentence now"). The ZephCore sentence in the 12-hour paragraph now says rtc: clear the RV3028 12-hour bit at boot liquidraver/ZephCore#106 takes no time from the chip if Control 2 is unreadable or reads FFh, or if the clear or the re-read fails; the next sync then sets the clock. Description only: no code change, no push, head still 0f038054. Checked against rtc: clear the RV3028 12-hour bit at boot liquidraver/ZephCore#106's own description first, read back after posting, and confirmed by the ZephCore session.
• Answered the Zephyr session's read-only boot-recovery question, using dev and Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421, Store RV3028 backup switchover and trickle charger config in EEPROM 🤖🤖 meshcore-dev/MeshCore#3545 and Adopt an RTC only if its time registers read like that chip 🤖🤖 meshcore-dev/MeshCore#3544:
  • MeshCore adopts the chip on an address ACK alone. A chip with no ACK is never re-probed that boot.
  • Read and write the RV3028 clock atomically, and reject switchover-garbled transfers 🤖🤖 meshcore-dev/MeshCore#3421 confirms 24-hour mode and BSF on every read and write, retries reads on every call, and retries an unconfirmed write every 5 s, at most 13 attempts per set.
  • Store RV3028 backup switchover and trickle charger config in EEPROM 🤖🤖 meshcore-dev/MeshCore#3545 retries the switchover config 3 times, 10 minutes apart.
  • dev's unchecked set24HourMode() can write FDh to Control 2.
  • The Zephyr session confirmed this is enough.
• No upstream activity from maintainers since link Session Handoff [rv3028-eeprom]: MeshCore #3421 converged at 0f038054 after an all-PASS acceptance matrix; RV3028 position frozen #23.

What not to repeat

• Checking a posted description by cmp against the --jq .body file always reports one extra trailing newline on the round trip. Compare with diff, or strip trailing whitespace, before calling it a mismatch.

New learnings

• None that aren't already recorded. The boot-recovery comparison lives in the Zephyr session's draft issue and in step 6 above.