Problem to use libfat on my r4i card

Hi

I have a R4 2014 3DS upgrade SDHC Revolution for RTS lite www.r4isdhc.kk. Like this image but with different web site so i think it's a clone.
https://i.servimg.com/u/f38/18/89/68/64/ds_chi12.jpg

I wish to test my chip-8 emulator with libfat to read files on SD. I have the message : fatInitDefault failure



I tried using dldi patcher for my roms, even if my cards seems to...

Problem to use libfat on my r4i card