cannot mount SDCard on RP2040 Adalogger

[WMXZ-EU]

I wanted to use the SDCard that is part of the Adafruit Feather RP2040 Adalogger. As there is no prebuild MPY for the Adalogger I use the Feather prebuild. I installed the sdcard using Thonny.
Now I run the script

import uos
from machine import SPI,Pin
from sdcard import SDCard

sd=SDCard(SPI(0),Pin(23))
print(sd.spi)
print(sd.cs)
uos.mount(sd,'/sd')

and get

MPY: soft reboot
SPI(0, baudrate=1263157, polarity=0, phase=0, bits=8, sck=18, mosi=19, miso=20)
Pin(GPIO23, mode=OUT)
Traceback (most recent call last):
  File "<stdin>", line 8, in <module>
OSError: [Errno 19] ENODEV

The pins are the one given for the Adalogger product and are working perfectly in Arduino and Circuitpython.

It is not the disk, because if I, without touching the disk, install CPY all is working.
The disk is an exFAT formatted 64 GB disk, but that should for fatfs (oofatfs) not be a problem (also it is working for CPY). Arduino uses SdFat, but I'm familiar with fatfs, that had exFAT support earlier than SdFat.

I also tried to replace the uos.mount(sd,'/sd') by uos.mount(vfs.VfsFat(sd),'/sd'), but same error.

Any hint on the problem would be appreciated.

PS: I have no issue with my Arduino program, but wanted to demonstrate the feasibility of Python. The CPY basically works, but is (by design?) somewhat closed.

Edit:
Using

buf=bytearray([1]*512)
sd.readblocks(67328,buf)
print(buf)

I could indeed access the Wav file stored on the disk (I got the sector number from HxD

EDIT:
same with RP2040 pico: can read correct sector from SDCard, but os.mount(sd,"/sd") fails.
SD card was reformatted with tool from official "SDCard Formatter"

[mendenm]

have you tried something like:

    vfs = os.VfsFat(sd)
    os.mount(vfs, "/sd")

to declare the right filesystem type?

[WMXZ-EU]

Tried just that, but same ENODEV

[mendenm]

OK, just to see if it helps, can you try the cleaned-up SD card driver I wrote, at:
micropython/micropython-lib#765
You really just need:
https://github.com/mendenm/micropython-lib/blob/master/micropython/drivers/storage/sdcard/sdcard.py

[robert-hh]

[Errno 19] ENODEV usually means, that the card can be accessed at block device level, but the file system is not found. I do not know whether MicroPython supports exFAT. All cards I use are formatted with a single FAT32 partition. Specifying the file system in the mout command like you did with uos.mount(vfs.VfsFat(sd),'/sd') cannot hurt.

[mendenm]

oops, I didn't notice the exFAT when I made my previous comment. @robert-hh is probably correct in observing that that isn't supported.

I retract any expectation that my previous suggestion might help.

[WMXZ-EU]

OK, will try with a smaller disk and FAT32. As I know that Elm Chan's fatfs supports exFAT and MPY is using fatfs, any suggestion on where to start to check the missing bit?

Anyhow: the modified sdcard.py did not help

[WMXZ-EU]

Issue solved:
ExFAT must be activated in fatfs. So far, only three stm32 boards (Arduino_nicla_vision, Arduino_giga, Arduino_opta) had this done

inserting
#define MICROPY_FATFS_EXFAT (1)
into mpconfigboard.h enabled ExFat and sdcard was mounted correctly
Thanks for helping me

[robert-hh]

Good that you found it. I was just about writing the same answer.