put the card in th PC and edit config file with notepad. When you edit config.txt remotely, when Batocera is running, the boot partition is mounted in read-only mode, alternatively, if you want to modify config.txt with Batocera running, before edit config.txt, in ssh console you must write:
mount -o remount, rw /boot
To remount boot partition un read and write mode, once modified the file, write
mount -o remount, r /boot
To remount boot partition again in read only mode