NEXUS-XR cancel black box data download causes 'dead' system

[karstendf]

Current Behavior

There seems to be a problem if the download of black box data (from within Configurator) is aborted before completion by pressing the 'Cancel' button. In my case, that lead to the flight controller being completely 'dead' after reboot from an application point of view (LEDs continuously lit, no connection possible).
Boot loader access did work though, and so did re-flashing INAV firmware with full chip erase. However this did not bring the controller back to life.
In this situation, after waiting for ~7 minutes (I'd assume time varies w/ the amount of data in the black box), the FC LEDs start to flash and the controller becomes accessible again.
From there, it is possible to cure the problem by issuing a flash_erase command via terminal - after exit / reboot, the FC is back to normal.

Steps to Reproduce

1. let the FC record a significant amount of black box data
2. start a download of black box data from Configurator's black box tab
3. abort the download by pressing 'Cancel' button
4. reboot
   => to be honest, I did not attempt to reproduce this yet - I'm too afraid to completely brick my Nexus..

Expected behavior

FC becomes accessible after reboot after above sequence of actions within < 60s

Suggested solution(s)

Check if there is a process related to the Nexus X black box that survives restarts and even re-flashing of INAV firmware, which blocks startup of INAV

Additional context

last 'diff all' before the problem occured

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• FC Board name and vendor: Radiomaster NEXUS-XR
• INAV version string: # INAV/NEXUSX 9.1.0 Jul 8 2026 / 02:10:25 (1531750), # GCC-13.2.1 20231009