Fix blackbox corruption when no motors defined in mixer #11220
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Problem: - Field definitions use AT_LEAST_MOTORS_N (checks motorCount AND flag) - I-frame write used MOTORS (checks flag only) - When motorCount=0 and flag=true: header declares 0 fields, I-frame writes 1 byte - motor[0] - getThrottleIdleValue() = 0 - 0 = 0 → encodes as 0x00 - Decoder expects frame marker, finds null byte → catastrophic failure Fix: - Change I-frame write from FLIGHT_LOG_FIELD_CONDITION_MOTORS to FLIGHT_LOG_FIELD_CONDITION_AT_LEAST_MOTORS_1 - Change P-frame write for consistency - Now matches field definition condition exactly Testing: - Board with motorCount=0, MOTORS flag enabled - Before: 207 decoder failures (0.050s duration) - After: 3 decoder failures (12s duration) - matches baseline Files: - src/main/blackbox/blackbox.c lines 1079, 1346 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
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Summary
Fixes blackbox log corruption that occurs when BLACKBOX_FEATURE_MOTORS is enabled but no motors are defined in the mixer (e.g., after
mmix resetor on fixed-wing with servos only).Problem
When
getMotorCount() == 0but the MOTORS feature flag is enabled, the encoder writes a spurious null byte in I-frames, causing the decoder to fail catastrophically with most frames failing to decode.Root Cause
Condition mismatch between field definitions and write functions:
AT_LEAST_MOTORS_1(checks motorCount >= 1 AND flag)MOTORS(checks flag only)Changes
MOTORStoAT_LEAST_MOTORS_1MOTORStoAT_LEAST_MOTORS_1(consistency)Testing