ENODEV error when creating files after building custom MicroPython OTA firmware

[aravikyr]

Hi,

I’ve built a custom MicroPython firmware for ESP32-S3 (16 MB flash) with OTA support. After flashing, when I try to create or write files on the device, I get:

OSError: [Errno 19] ENODEV

Thonny also reports:

Exception while handling 'write_file' (OSError: Could not open file /test.py for writing)

The firmware build was done using the latest ESP-IDF, and _boot.py is included in the build. I suspect it might be related to VFS or flash partition setup.

Questions:

Has anyone encountered ENODEV after building a custom MicroPython firmware for ESP32 with OTA?

Are there specific settings in mpconfigport.h or partition table configurations needed for file system access?

Could this be related to frozen modules or missing VFS mounting in the build?

Firmware info:

• MicroPython v1.1.0-preview (trial)

• ESP32-S3, 16 MB flash

• Built with custom OTA support

ESP32_GENERIC_S3.zip
partitions-16MiB-ota.csv

Any pointers would be appreciated.

[shariltumin]

Try erasing the flash before flashing the new OTA firmware. The partitions may not be the same as the previous firmware.

[shariltumin]

I compiled a firmware using your partitions table.

 >>> from flashbdev import bdev
>>> bdev.info()
(1, 129, 2359296, 14417920, 'vfs', False)
>>> import os
>>> os.statvfs('/')
(4096, 4096, 3520, 3517, 3517, 0, 0, 0, 0, 255)
>>> 

Seem is it working.

[aravikyr]

Can you share the Commands...

[shariltumin]

What result you got for flashbdev.bdev.info()?

[shariltumin]

You need to import flashbdev first, do this in REPL

>>> import flashbdev
>>> flashbdev.bdev.info()