[BUG] MMC support on MaixDuino

[Heinrich Schuchardt]

Hello Sean,

thanks for getting MMC running on the MAIX.

Reading files works fine. But if try to write I get a failure:

=> save mmc 0:1 ${loadaddr} foo 0x100
mmc write failed
Error: writing contents
** Unable to write file foo **
=> ls mmc 0:1
** No partition table - mmc 0 **
=>

Even after resetting the board the SD-card cannot be read.

Only after power-cycling the SD-card works again:

=> ls mmc 0:1
       377   boot.scr
     30349   dtb
   2155040   uImage

3 file(s), 0 dir(s)

Best regards

Heinrich