STM32L476RG always delivers FR_DISK_ERR when using f_mount, to mount a micro-SD card with FATFS.

[EYako.1]

The SD card itself seems to work flawlessly with my computer. I tried all the configurations offered in the forum for those who had a similar issue (setting DMA or the interrupt timer) and it doesn't seem to help. Stepping through the function with the debugger seems to change the result (giving out FR_NOT_READY instead of FR_DISK_ERR ), so I don't really know where thing go wrong.

What else can I try to do to fix this?

[Tesla DeLorean]

On a Nucleo board, or something else?

If not Nucleo, what USART and pins are used for debug/diagnostic output?

Show socket and wiring.

[EYako.1]

Yes its a Nucleo board. I used the internal pullups for all the ports expect CLK, and just plugged the SD card to the board with jumper cables.