# Recovery 3001 0.4.0 Beta 1 Dev 9

Dev 9 is a Windows development build focused on trustworthy interrupted-image
resume. It is not a signed commercial GA release.

## Added

- Persist a `.partial.json` checkpoint at the start and after every completed
  image chunk.
- Preserve the complete read-error map across cancel and resume.
- Bind the checkpoint to source stable ID, capacity, sector size, exact partial
  length, and partial-image prefix SHA-256.
- Add a deterministic checkpoint audit covering cancel/resume, mismatches, and
  tampering.

## Fail-closed behavior

- A non-empty partial image without its checkpoint cannot resume.
- A checkpoint from another device, capacity, sector size, or image length
  cannot resume.
- A changed checkpoint payload or changed partial-image prefix cannot resume.
- Legacy core callers cannot bypass the checkpoint requirement.
- The checkpoint remains after cancellation or failure and is removed only
  after the complete image manifest is written.

## Verification

- Rust workspace tests: 70 passed, 0 failed.
- Focused checkpoint tests: 7 passed, 0 failed.
- Focused GUI/CLI checkpoint path tests: 2 passed, 0 failed (9 total focused).
- Clippy all targets and features: 0 warnings.
- Windows GUI and CLI Release builds: passed.
- Source-device write commands: 0.
- Existing Dev 8 image-fault, Dev 7 FAT32, Dev 6 session/preview,
  FAT32/exFAT 1,000-file, and nine-environment evidence remains preserved.

Executable, audit, and package SHA-256 values are recorded in
`BUILD-VERIFICATION.txt` and the public version index.

## Remaining external release gates

- Long physical read-error and disconnect endurance testing.
- Separately provisioned physical fragmented FAT32 and exFAT USB devices.
- Additional USB vendors and capacities.
- Actual Windows 10 x64 run.
- At least four of five unsupervised users complete the workflow without
  external documentation.
- Windows code-signing certificate and signed installer or portable package.

Android remains deferred and is not included in this release.
