I know about Clonezilla and copy pasting partitions with gparted, but can I just use dd to copy a partition with batocera to a USB stick and will it then boot from the stick? Do I have to set the boot flag or take any other steps?
Thank you for any tips.
It is possible to boot from a single partition, USB live images work this way. But regular installation that OP wants to clone likely has a separate partition.