Usb sounds

Hi
first let me say thanks for this awesome project.
I had the sound box working with default sounds.
fallow the instruction to add media to Usb Stick
plug my usb into the soundbox boot and nothing works
get an error : mmc1 error 110 whilest inialiting SDIo card

if I remove usb and reboot it works

I had try 2 usb stick same error.
usb are fat32
with folder on root like this

0 Piano
1 Korg

any advice how to play from usb stick