OpenMV N6 — Cannot access SD card from MicroPython scripts

OpenMV Boards
1

Board: OpenMV N6 (STM32N657X0)
Firmware: v4.8.1 / MicroPython v1.26.0-77
OS: Windows 11
IDE: OpenMV IDE v4.8.x
SD card: ~1 GB, FAT16, formatted with official SD Card Formatter from sdcard.org

Problem: When I insert a FAT16 formatted microSD card into the N6 and try to access /sd from a MicroPython script in the IDE, I always get:

OSError: [Errno 19] ENODEV

The SD card shows up correctly as a USB drive (D:) on my Windows PC with the .openmv_disk marker file visible. However, /sd is never accessible from scripts.

What I have tried:

  1. Ejecting D: in Windows Explorer before running the script
  2. Power-cycling the N6 with SD card already inserted, then ejecting D: before connecting IDE
  3. Reformatting the SD card using the official SD Card Formatter tool (result: FAT16, 16KB cluster)
  4. None of these allow /sd to be accessed from MicroPython. The internal /flash works fine.

Question:
Is there a way to disable USB mass storage for the SD card so MicroPython scripts can access it directly? Or is SD card write access from scripts not yet supported on the N6 in firmware v4.8.1?

Thanks

Swathi

2

It’s called /sdcard for OpenMV Firmware.

3

Thanks It works now. BTW can I load and run tflite models on N6 device directly by storing them on sdcard?

4

No, they need to be in the romfs.