Fixing OpenSUSE's 'No Devices Matches MBR Identifier'

Check the file in the subfolder boot/grub/mbrid. Do sudo fdisk -l and check that the ID of your usb stick is the same as the one in the file. If not, change it. Just deleting the file won't work, then the code will assume you want to boot from CD or DVD and fail if it doesn't find one. But you can also try to boot with the kernel parameter nombridcheck. But unfortunately for me nothing worked. It seems OpenSUSE USB boot is pretty broken ...