Does the method described in the manual (copying to /dev/sdX) work under UEFI? Or it's basically the same thing as copying to a partition?
i made a mistake, of course. This time when copying the ISO:
Wrong: dd if="$image_path" of="$dev" bs=1M
Right: dd if="$image_path" of="$dev"1 bs=1M
If you perform the wrong command, then the parted MBR gets overwritten
by the isohybrid MBR of the Debian ISO.
Have a nice day :)