I've just been messing around with the x86 (x64) version on an Acer R3700 which runs an Intel Atom D525 with the Nvidia Ion chipset (a fellow user posted about this within the last month regarding HDMI audio - thanks for that as that helped me!)
Problem I've found is that when using the built in SD card slot, the card becomes read-only. Confirmed by:
1) No auto expansion when copying ROMs over (apologies but I assume, based on the size that this should expand)
2) Not retaining the few ROMs I'm able to cover over, between reboots
I launched GParted and was unable to expand the partition from the 1.2GB that the disk image comes with (tried Etcher, Win32diskimager to build the SD card). However, when I moved the card into a USB converter and then used GParted, it allowed me to expand the disk. Now when I'm in Batocera is allows me to use all the space (as confirmed with a 'df -h' via SSH) and that it retains my ROMs between reboots.
Any idea why the SD card slot would mount as read-only? Thanks.