Thanks,brother.
Umm......I think you can suggested other users use DiskGenius to make a partition backup from partition 1# before any update.
At 5.18 update to 5.19 same wrong happen,I'm see ID call "GameCast" say use boot.img.xz for replace,but nothing happen,I don't know have any idea so rewrite a full version image files.
When I use a week to copy all games,setup all config and remake all links,use live CD to boot and see have what's files on my disk.a hours pass,I think all changes save on /dev/sda2,so if have any update maybe it's write on /dev/sda1.but I'm not sure just file "batocera" on changed or grub changed too,so I'm backup my /dev/sda1 partition on my other computer.In this time,I'm from 5.18 update to 5.20 and black screen again,power off device,remove disk and link on other computer,use backup files to replace all files on /dev/sda1,power on,system is back to 5.18 and no problem.
