# Controller A USB Feature Parity — Host Durability Failure

Status: complete
Result: historical failure evidence; successor Controller A parity qualification complete
Type: evidence
Updated: 2026-08-01
Next Action: none; retain this original failure snapshot and use the completed successor workpackage for current disposition
Campaign: 003-complete-bounded-hpt-slow-export-firmware-ticket
Parent: work/checklists/checklist-controller-a-complete-usb-feature-parity-regression-with-raspberry-pi-verification.md
Canonical Truth: docs/firmware-update-validation-and-recovery.md and
docs/sd-card-operation-and-recovery.md
Successor: work/wp/completed/wp-diagnose-and-mitigate-controller-a-usb-false-success-durability.md
Final Evidence: work/evidence/controller-a-a2-exact-b-profile-comparison-20260728.md

## Final Disposition

This remains valid evidence of the original host-durability failure. The later
successor workpackage and exact-profile evidence resolved the open Controller A
parity question, so this snapshot has no current next action.

## Identity

- Controller/J-Link: `1751136` / `69664082`
- S-record SHA-256:
  `486B048B65BCE801CA26DD6B4448F11B92F6B4C815DAFE082E48CBD4F170CCF9`
- SD CID: `035344535330384780976F0084018559`
- USB: PNY serial `071C49DE246A1F97`, label `A-CTRL-2`, UUID `8B67-9B27`

## Controller-reported results

- Program/verify/reset/run: pass.
- WAV discovery/load and SOUND_1 triggers: pass; zero system errors.
- IMX save: result success, `8388864` bytes, 257 writes, 32768-byte maximum.
- Same-image update: result success, zero FileX errors, exact 256-read
  preflight/staging shape.
- Four-MiB flash SHA-256 before/after update:
  `F6CFD8FAC0EA9C8F25D04A21B0F418B1B05BD4FC1750FBECFD347D470D1F5C7E`.
- PID capture trigger returned accepted and the workflow returned idle.
- HPT request `1`: PUBLISHED/COMPLETE, `3027` healthy records, zero gaps,
  ten writes capped at 16384 bytes, readback/sync/STOP reported successful.

## Independent Pi result: failed

After removal, read-only Linux inspection found a clean FAT filesystem with no
differing FAT copies or orphaned clusters, but the root contained only the
three pre-A files:

- `SMI7_00112233_20260725t0911-20260727t1048.csv` (`146573` bytes);
- `W00.wav` (`198566` bytes);
- `W01.wav` (`176516` bytes).

No new IMX, PID text, or A-run HPT CSV existed. No temporary or backup
publication files existed. The WAV hashes still matched the canonical set.
Therefore Controller-side success/readback is not host durability proof on
Controller A, and A/B USB parity has not passed.

Controller A was finally reset without USB. Final capture reported USB mounted
`0`, system errors `0`, idle audio/progress, no stale filenames, and unchanged
SD CID.

Raw captures remain under the ignored
`work/evidence/hpt-log-store-circular-mirror/controller-a/generated/usb-complete-parity-20260727/`
tree.
