14.1.1.3.5.5. Erasing the internal filesystem

Every camera has a small writable FAT filesystem (where main.py and user files live, separate from any SD card). Erasing it is the fix when a bad main.py or a corrupted filesystem prevents the camera from booting. In OpenMV IDE this is the Erase internal file system checkbox in Load Custom Firmware; the command-line equivalent differs by camera family.

14.1.1.3.5.5.1. OpenMV cameras with the openmv_dfu bootloader

The bootloader exposes a dedicated erase DFU alt. Write a small zero-filled file to it (a 4 KB block of zeros is plenty – it clears the filesystem header so the camera reformats on the next boot) with --reset:

dd if=/dev/zero of=erase.bin bs=4096 count=1
dfu-util -w -d ,<DFU VID:PID> -a <erase alt> --reset -D erase.bin

Camera (TARGET)

DFU VID:PID

Erase alt

OpenMV Cam M4 (OPENMV2)

37C5:9202

-a 1

OpenMV Cam M7 (OPENMV3)

37C5:9203

-a 1

OpenMV Cam H7 (OPENMV4)

37C5:9204

-a 1

OpenMV Cam H7 Plus (OPENMV4P)

37C5:924A

-a 3

OpenMV Pure Thermal (OPENMVPT)

37C5:9205

-a 3

OpenMV Cam N6 (OPENMV_N6)

37C5:9206

-a 2

OpenMV AE3 (OPENMV_AE3)

37C5:96E3

-a 5

The OpenMV AE3 has a single writable FAT filesystem shared by both Cortex-M55 cores, erased once via -a 5. There is no separate per-core filesystem erase.

14.1.1.3.5.5.2. OpenMV Cam RT1062

The RT1062 has no DFU bootloader; erase its FAT disk’s master boot record (at 0x60400000) with the SPSDK flashloader, which forces a reformat on the next boot:

blhost -u 0x15A2,0x0073 -t 120000 -- flash-erase-region 0x60400000 0x1000

14.1.1.3.5.5.3. STM32 Arduino boards

The Portenta H7, Giga, and Nicla Vision erase by absolute address rather than an alt:

dd if=/dev/zero of=erase.bin bs=4096 count=1
dfu-util -w -d ,<DFU VID:PID> -a 0 -s 0x08020000 -D erase.bin
dfu-util -w -d ,<DFU VID:PID> -a 1 -s 0x90000000 --reset -D erase.bin