Wondering if anyone else can confirm this...
I have Batocera installed on the HDD in my laptop. If I write the latest Batocera image to a USB thumbdrive (for testing) and try to boot from it, the system still boots from Batocera on the HDD.
FYI...this is not an issue with the newly created thumbdrive, If I use Gparted Live to wipe the HDD (or remove the HDD), I am able to boot the same thumbdrive without issue. It's as if the HDD is taking precedence even though I told it to boot from USB.