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Ensure SD cards are formatted using MS-DOS (FAT32) using MBR (Master Boot Record)
Ensure SD card is not over <= 32GB in capacity
Ensure the clock for SDMMC is set according to your SD card speed, (i.e. if your card is rated for 10MB/s speed, set the SDMMCCLK to just under that, something like 8MB/s with 0 clock divider)
Ensure file names follow 8.3 format
All FATFS function calls return a
FRESULTerror code, printing them out is helpfulFATFS Error Codes: http://elm-chan.org/fsw/ff/doc/rc.html
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