fix: add stabilization delay to prevent write failures (error 0x27)#40
Merged
wizzomafizzo merged 2 commits intomainfrom Jan 20, 2026
Merged
fix: add stabilization delay to prevent write failures (error 0x27)#40wizzomafizzo merged 2 commits intomainfrom
wizzomafizzo merged 2 commits intomainfrom
Conversation
When using WriteToNextTag, writes frequently fail with error 0x27 ("wrong
context for command") on the first attempt. This occurs because the card
may still be moving when detected, causing RF field instability that makes
the PN532 lose target selection.
Changes:
- Add 75ms stabilization delay in executeWriteToTag before attempting write
- Add error code 0x27 to IsRFError() so it's retryable via existing logic
- Add test case for 0x27 error classification
The stabilization delay matches the existing pattern in tagops.InitFromDetectedTag
and prevents most 0x27 errors. Classifying 0x27 as an RF error enables retries
for any remaining edge cases.
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Summary
executeWriteToTagbefore attempting write operationsIsRFError()so it's retryable via existing retry logicProblem
When using
WriteToNextTagfrom zaparoo-core, writes frequently fail with error 0x27 ("wrong context for command") on the first attempt but succeed after retrying. This occurs because:InListPassiveTargetdetects the tag AND selects it as target 1executeWriteToTagis called immediately (no stabilization delay)SendDataExchangefails with 0x27 because target 1 is no longer validSolution
The stabilization delay matches the existing pattern in
tagops.InitFromDetectedTagand prevents most 0x27 errors. Classifying 0x27 as an RF error enables retries for any remaining edge cases.Test plan
make check)