Hi:
I have the same issue, it seems like there is a problem and batocera just can not detect the EXT partition. I had connect my usb to my PC and the EXT partition "SHARE" where several folders including the roms path is present.
I even can not change the UI language, have you been able to change some configuration and made it persistent?
I do not know if maybe it is an issue with the usb, I burned the batocera image onto a sd card (2Gš and it works fine.