Blackbox data / On board flash will not erase

[scul86]

Current Behavior

On board flash will not erase the data already stored on the chip.

# flash_info 
Flash sectors=1024, sectorSize=131072, pagesPerSector=64, pageSize=2048, totalSize=134217728
Paritions:
  0: FLASHFS   0 1023
FlashFS size=134217728, usedSize=104548352

# flash_erase 
Erasing...
Done.

# flash_info
Flash sectors=1024, sectorSize=131072, pagesPerSector=64, pageSize=2048, totalSize=134217728
Paritions:
  0: FLASHFS   0 1023
FlashFS size=134217728, usedSize=0

After a power cycle:

# flash_info
Flash sectors=1024, sectorSize=131072, pagesPerSector=64, pageSize=2048, totalSize=134217728
Paritions:
  0: FLASHFS   0 1023
FlashFS size=134217728, usedSize=104548352

Also, if I use the blackbox tab "Erase Flash" button, then click "Save and Reboot", I get the log message "You need to upgrade your firmware before you can use the Blackbox tab."

in context:

2026-02-28 @ 11:09:26 -- EEPROM saved: Configuration
2026-02-28 @ 11:09:26 -- Device - Rebooting
2026-02-28 @ 11:09:26 -- MSP connection successfully closed
2026-02-28 @ 11:09:33 -- Connected to: /dev/ttyACM0 @ 115200 baud
2026-02-28 @ 11:09:33 -- MSP connection successfully opened with ID: 11
2026-02-28 @ 11:09:33 -- You need to upgrade your firmware before you can use the Blackbox tab.
2026-02-28 @ 11:09:37 -- MultiWii API version received - 2.5.0

Steps to Reproduce

1. Connect to FC via Configurator
2. Issue cli flash_info
3. Note usedSize value
4. Issue cli flash_erase
5. Repeat steps 2 & 3, note usedSize=0
6. Power cycle the FC and reconnect via Configurator
7. Repeat steps 2 & 3, and observe the used space was actually not erased. usedSize is same as value noted in step 3.

Expected behavior

On board flash / blackbox data is erased, ~100% free space after a power cycle.

Suggested solution(s)

Not sure, willing to provide additional troubleshooting as needed.

Additional context

diff - https://pastebin.com/C1ZgH1cG

Similar to this 2020 issue which was resolved with v2.5 - #5704

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• FC Board name and vendor: INAV/RADIOLINKF405
• INAV version string: 9.0.1 Feb 13 2026
• INAV Configurator: 9.0.2