# USB09 recovery-candidate Pi failure inspection

Status: complete
Type: evidence
Updated: 2026-08-01
Next Action: none; retain as historical failure evidence for the resolved USB09 incident

Project Map: work/maps/map-smi-firmware-stabilization-and-qualification.md
Workpackage: work/wp/completed/wp-restore-broad-usb-compatibility-baseline.md
Checklist: work/checklists/checklist-stage-1b-four-drive-usb-compatibility-baseline.md
Incident: work/incidents/incident-usb09-false-write-failure-and-usb-compatibility-architecture-correction.md
Controller evidence: work/evidence/usb09-recovery-candidate-controller-failure-20260731.md

## Identity and method

The Pi identified the unchanged incident specimen by canonical label `USB09`,
FAT UUID `24E4-9846`, General UDisk serial `2512300955508200677718`, and
8,053,063,680-byte capacity. The partition was unmounted before and after all
checks. Only no-repair FAT inspection, direct reads, a read-only mount, and
hashing were used.

## FAT state

`fsck.fat -n -v` reached the final filesystem sector and reported:

- both FAT copies appear intact but differ;
- FAT1 was selected for the read-only traversal;
- free-cluster summary `245615` versus actual `245612`;
- 6 files using 19 of 245,631 data clusters;
- the unchanged Windows root-label versus blank boot-label convention;
- return code `1`, with the filesystem explicitly left unchanged.

The complete FAT copies differ independently:

- FAT1 SHA-256:
  `E4111D42F5A317358A57792586D089C78935423703BBE3A4ADE26E5D7DB399CD`;
- FAT2 SHA-256:
  `9ECB2E0EF181E26435D655C1BBB7F1863E16EC31E5EBE6CD55443BD44CC87A6A`.

## Publication artifacts

The requested final file `USB09_RCV.csv` does not exist. The root contains
`HPTE.TMP` with these properties:

- visible size 97,280 bytes;
- SHA-256
  `E1E03C60A698FA4CA2C7639460D998B506F9075FF157F51768354264FDE0DC53`;
- valid export header and requested range;
- final readable text ends partway through record `1926`;
- no `Export completion: COMPLETE` marker.

Controller telemetry recorded 99,328 requested bytes in 97 calls of at most
1,024 bytes. The FAT-visible temporary file is therefore 2,048 bytes shorter
than the requested count after the 50-second `fx_file_close()` failure.

The prior valid incident export
`SMI6_07162026_20260725t0836-20260730t1541.csv` remains 374,707 bytes with
unchanged SHA-256
`D675AF49DDE995139EE12E734570E76D7D33AD5F95C3FD310876C0243821B951`.

## Kernel state and disposition

The Pi logged no USB reset, SCSI sense, medium, device-offline, buffer-I/O, or
block-I/O error during reinsertion and read-only inspection. USB09 remains
unmounted.

This is a correctly reported failed publication, not a false terminal result:
the temporary file is incomplete, the destination was not published, and FAT
metadata is inconsistent. Stage 1B and Stage 2 remain blocked. Diagnose the
FileX close/driver path and raw `0x5C` origin without repairing USB09 or adding
drive-specific behavior. Raw `0x5C` is USBX `UX_TRANSFER_TIMEOUT`. The next
candidate changes only the HPT FileX cap to the previously accepted 32 KiB
value; USB09 and the broad matrix remain required before promotion.
