# Idea Brief: HPT2 Personality Update Floor at 00-05-01

Status: exploring
Type: idea-brief
Updated: 2026-09-23
Next Action: keep SMI bench work paused; preserve accepted candidate 00.05.01-1bf8afe6aeba-6476100e5ae5 and its controller-generated IMX while the separate DisplayTest lane produces and controls the missing 01-01 IMX
Readiness Review: run explicitly with ts: bs review; ordinary brainstorming does not review
Produces:

## Current Synthesis

### Idea

Release SMI 00-05-01 with a minimum compatibility floor for ordinary updates and a separate, deliberate service rollback to any valid SMI image. Use the existing IMX header Title as the source of candidate family and version identity, together with MachineMask, layout, and CRC checks. The external USB filename may be changed by an operator and is not an identity input. No new header field is required. SMI accepts a FAT32 DisplayTest handoff, performs explicit HPT2 initialization, and permits return to DisplayTest 01-01 or later. Every admitted target carries a media requirement: existing verified FAT32 is retained, another readable classified layout is formatted when the target requires FAT32, and missing or unreadable required media stops before QSPI erase. A FAT32-era rollback uses the same preparation transaction; field card replacement is not a supported workflow.

### Why It Matters

Controller B running older DisplayTest showed a persistent white screen with HPT2 media. It booted after the expendable card was formatted FAT32. An ordinary downgrade from HPT2 personality firmware to FAT32-era firmware could leave an installed controller without display access. Field access to the internal SD card is impractical, so a rare recovery downgrade must prepare the installed card in place. The SMI 00-05-00 development line supports HPT2 but does not have the normal-update guard and was never deployed on a production controller; a new release is required.

### Desired Outcome

- SMI 00-05-01 identifies the candidate before any QSPI erase: bounded numeric version and family parsed from the validated IMX header Title, intended machine from MachineMask, and existing integrity/layout checks. Require the identity fields within the Title to be consistent. The external USB filename is used only to discover an `.imx` candidate; renaming it does not change acceptance.
- In the ordinary updater, admit recognized approved HPT2-capable SMI, CVO, or DVO personality images only at 00-05-01 or later. Reject older, unknown, inconsistent, or unparseable personality identities before erase and leave firmware bootable and SD media untouched.
- The ordinary cutoff refuses SMI 00-05-00 despite its HPT2 logger. Focused host policy tests cover that below-floor refusal; target qualification does not install 00-05-00. A separate service rollback admits any valid SMI image without a version allowlist. SMI 00-05-00 or later uses HPT2; pre-00-05-00 SMI requires explicit in-place FAT32 preparation. Do not require an intervening DisplayTest installation.
- For every FAT32 target, validate and stage the complete selected IMX before changing SD media; dispose of required history and obtain explicit data-loss confirmation when conversion is needed, recheck the installed card CID and a representative sector, retain verified FAT32 without formatting, format another readable classified layout, revalidate the staged image, and then use the ordinary internal-flash replacement path. A missing/unreadable card or failed preparation/staging step must not start internal-flash replacement.
- If current SMI remains bootable with a usable UI after rollback stops, existing service 471 can explicitly reinitialize the card as HPT2, with the prior card data already lost. QSPI staging may affect UI resources even before internal-flash replacement; target fault tests must prove the actual USB-updater and service-471 recovery boundary. Failure after internal-flash replacement starts has the same recovery risk as any firmware update.
- Guarded SMI permits return to DisplayTest 01-01 or later by validated Title. The revised DisplayTest must boot safely with HPT2 media and tell the operator that normal production testing requires a FAT32 card. Its fixture-to-fixture updater rejects DisplayTest versions before 01-01. After verified FAT32 handoff, its personality updater can admit valid older SMI images; the 00-05-01 ordinary personality floor applies in SMI while the card may be HPT2. DisplayTest 01-00 is excluded from the SMI return path.
- SMI accepts eligible FAT32 media from the DisplayTest fixture and initializes HPT2 only through an explicit service action with data-loss warnings, confirmations, card identity recheck, and disposition of required FAT32 history. The main chart button must use its gray disabled appearance and reject clicks whenever the logger queue, card format, media session, or HPT2 store cannot accept records. Verify logging, retention, history, and export. Already ready HPT2 media is not needlessly reinitialized.
- Prove installation from old and revised FAT32 DisplayTest handoffs on both controller assemblies. Prove renamed USB files with valid Titles remain eligible, legacy IMX images are rejected by the ordinary updater before erase, and a DisplayTest 01-01 or later return boots safely with HPT2 media. Separately prove direct service rollback with representative valid HPT2-capable and FAT32-era SMI images, including FAT32 preparation and service-471 recovery after pre-flash failure where applicable.

## Constraints And Non-Goals

- CVO and DVO are outside this project. Do not alter DVO in this lane; this project implements and qualifies SMI only.
- DisplayTest uses a separate 01-xx version series. The normal return floor is 01-01; unknown or older DisplayTest images default to refusal. Identify exact specimens for qualification, not for a production allowlist.
- Field SD-card removal or replacement is not a practical recovery step. Service 471 initializes HPT2, not FAT32; the FAT32-era rollback requires a distinct explicit FAT32 preparation action.
- No update workflow may promise a working touch screen after a failed internal-flash replacement. That risk is common to upgrades and downgrades; it is not a downgrade-specific reason to prohibit the service path.
- MachineMask alone does not establish product identity or SD compatibility. The version convention depends on controlled release discipline, not cryptographic authentication.
- Preserve published IMX files unchanged. Do not erase card data requiring retention without controlled disposition.
- This brief authorizes no code change, build, programming, format, power cycle, bench test, release, or rollout. Transition testing is paused.

## Shared Transition Contract

- DisplayTest normal production testing and Prep for Ship hand off verified FAT32 media; separate card-family qualification remains HPT2.
- Personality releases SMI, CVO, and DVO 00-05-01 and later signify HPT2 support.
- SMI 00-05-01 owns explicit FAT32-to-HPT2 initialization, the ordinary personality minimum compatibility floor, and a controlled direct service rollback to any valid SMI image with in-place FAT32 preparation when required. DisplayTest 01-01 or later provides a return path after safe HPT2-card startup and FAT32 handoff are proven.
- DisplayTest 01-01 may install a legacy personality only after its verified FAT32 handoff. This differs from the SMI ordinary updater's 00-05-01 personality floor and does not waive the SMI direct-rollback safeguards.
- Use separate project-bound Codex VS Code lanes. Related DisplayTest brief: FAT32 Production SD Handoff and Separate HPT2 Qualification in E:\dev\high_point\7520708_DispTest_FW.

## Open Questions

- Which exact DisplayTest 01-01 or later specimen will prove safe HPT2-card startup, fixture-to-fixture 01-01 floor, legacy personality admission after verified FAT32 handoff, and FAT32 production handoff?
- Which representative SMI specimens prove both HPT2-capable and FAT32-era service rollback without an image allowlist?
- Which exact released IMX specimens and target checks prove parsing, ordinary refusal before erase, direct rollback, format/recovery failure boundaries, and FAT32-to-HPT2 acceptance on both controller assemblies?

## Decisions

- Use existing IMX header information and the common 00-05-01 personality minimum.
- Apply that minimum to ordinary updates; provide a distinct service rollback for any valid SMI image. Do not force a DisplayTest hop for SMI rollback.
- Prepare the installed card in place for FAT32-era rollback after complete IMX validation and staging, with explicit data-loss consent and CID recheck. Service 471 remains the explicit HPT2 recovery action if current SMI survives a pre-flash failure.
- Treat the validated header Title as the source of family/version identity; do not require the external USB filename to match it.
- Permit return to DisplayTest 01-01 or later with safe HPT2-card startup and verified FAT32 production handoff. DisplayTest may then admit valid older personalities; its own fixture-to-fixture minimum is 01-01.
- Fail closed on unknown or inconsistent identity before erase.
- Fixture handoff remains FAT32; SMI performs explicit, warned HPT2 initialization after media identity and retention checks.
- Qualify the transition and refusal matrix on both controller assemblies, including renamed files, old and revised DisplayTest handoffs, host-proven below-floor refusal, representative service rollback, failure recovery, and safe return to DisplayTest 01-01 or later. Do not install SMI 00-05-00 for this qualification. Leave CVO and DVO outside this project; do not alter DVO.
- Bench testing remains paused until the owner resumes it.

## Exploration Log

### 2026-09-21

- Owner selected a common 00-05-01 minimum for SMI, CVO, and DVO HPT2 personalities, directed the next SMI revision to be 00-05-01, and requested separate Tool Shed entry points.
- Owner accepted the transition and media-preparation recommendations, required a return path to DisplayTest, and selected the IMX header Title as the candidate identity source because operators may rename the external USB file. The return floor was clarified to DisplayTest 01-01 or later, with safe HPT2-card startup and a reciprocal personality floor required before release.
- Owner added the rare direct SMI service-rollback need, rejected field SD-card swapping as impractical, and identified service 471 as the existing explicit HPT2 reinitialization path after a pre-flash failure. Ordinary upgrade and downgrade share internal-flash failure risk; the extra rollback requirement is controlled in-place FAT32 media preparation and data-loss handling.
- Owner clarified that service rollback may use any valid SMI image, with no version allowlist. The DisplayTest normal return minimum is 01-01, correcting an earlier 05.01 reference. Exact images remain qualification specimens and release evidence, not admission policy.

### 2026-09-22

- Read-only DisplayTest source review found that `src/DisplayTestUpdateAdmission.h` imposes no personality version floor; its fixture-to-fixture minimum is 01-01. DisplayTest's FAT32 handoff precedes personality installation. Its project record reports a Controller B FAT32 handoff and installation of SMI 00-04-11, with a power cycle needed after an initially unresponsive install tap; old SMI logging remains unproven there. The earlier reciprocal personality-floor language is superseded by the media-state contract above. SMI A/B return and rollback qualification remains open, and this project's bench pause remains in force.

### 2026-09-22 scope correction

- The owner confirmed that `7520553_SMI_00_05_00.imx` was never deployed on a production controller and does not need target qualification. It is removed from the physical transition path. The exact SMI 00-05-01 candidate will be installed directly through Settings > Update Firmware using a deterministic IMX built from the frozen Release S-record and released 00-04-11 audio resources.

### 2026-09-22 target-media and chart-availability requirement

- The owner requires an admitted FAT32 target to retain an already verified FAT32 card and to require a controlled format for any other readable classified layout. Missing or unreadable required media stops the update. Supported DisplayTest and pre-00-05-00 SMI targets require FAT32; ordinary SMI/CVO/DVO at 00-05-01 or later retain HPT2.
- The owner requires the main chart button to look disabled whenever the datalogger cannot record, including absent media or wrong format. The SMI implementation now uses live logger readiness and the existing gray disabled pixelmap.
- Controller A accepted and staged the prior 00-05-01 IMX but retained the old internal flash. That frozen candidate is superseded by this requirement change. Commit `10dbb91519384cc9144b94e8a79057c8f47c0630` contains the target-media and chart-availability implementation. Clean Debug and Release rebuilds reproduced the committed artifacts byte for byte, and immutable candidate `00.05.01-10dbb9151938-4e7dfb2f7333` validates with manifest SHA-256 `6F753689C56EFACE054C802FF782FFCC193BFAE2D7F5E948F0BE20F44FA86586`. Target proof remained open at this checkpoint; the 2026-09-23 entry below records the later evidence.

### 2026-09-23 current evidence

- Later watchdog, FCU command-lock, and ROM-cache corrections resolved the Controller A internal-flash handoff defect. A controlled self update completed with diagnostic error `0`, and the complete internal-flash readback exactly matched its candidate. The prior unresolved-transition statement is historical and no longer a blocker.
- Accepted candidate `00.05.01-1bf8afe6aeba-6476100e5ae5` is frozen from commit `1bf8afe6aebab3df4a8c71cb626e405ace3322f8`; its Release S-record SHA-256 is `6476100E5AE5B5ED5EA38F5BBFDFC8AE6BC44513200678406F2711B0B91C1D9D`. Controller A readback exactly matched the expanded image at SHA-256 `40560E9D046293BE345676BC97CD09E88E29D543DBEB02AD3B764EBF029D4E87`.
- The owner accepted the fitted Format 2 startup warning, reason-specific disabled-chart interaction, operator service 467 access, and service 471 warnings. The card was then initialized during review and returned ready with unchanged valid CID `05000C61736466672200001C8901A34F`.
- Controller A service 150 generated final SMI image `7520553_SMI_00_05_01.imx`, SHA-256 `AF8132D13837F6030CD73689E77833AA563C0C878C19126448E869DFEB337332`; all container CRCs validate and its main payload exactly matches the accepted Release candidate. The exact DisplayTest 01-01 IMX and the remaining A/B transition, refusal, rollback, and fault evidence are still open. Bench work remains paused.
