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STATUS_DEVICE_PROTOCOL_ERROR
The command completed with an invalid protocol sequence
A protocol error is different from a command the device explicitly reports as unsupported. It means framing, state, length, ordering, tag, phase or response contents did not satisfy the interface contract. Causes include firmware defects, stale state after reset, transport corruption or a driver using the wrong protocol revision.
Capture the raw transaction whenever possible. Resetting can restore operation but destroys the sequence that proves what went wrong. Compare negotiated version and capabilities before decoding fields, and confirm that concurrent requests did not reuse tags or buffers incorrectly.
What to inspect
- Record command bytes, response bytes, protocol revision, tags and transfer lengths.
- Correlate resets, timeouts and firmware events immediately before the malformed response.
- Test with known-compatible firmware and driver versions without weakening validation.
References
- Microsoft: Using NTSTATUS values
- Microsoft: Standard device reset interface
- Microsoft: Interpreting storage sense data
- Microsoft Open Specifications: NTSTATUS values
- ReactOS source: storage class PnP and error handling
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