Initialize an eMMC module

I connected an eMMC to the portenta h7 through the SDIO interface and I'm trying to access it in the code. However, I am unable to initialize and mount the block device, I always get an error and it doesn't seem to be working. While the code works fine for an SD card. Anyone has an idea on how to get this to work (an eMMC module on the portenta h7) ?

Thank you.