Comment # 17 on bug 984302 from Josef Reidinger

OK, I take this bug as it looks like problem with EFI detection. Is DVD booted
from EFI environment?

As workaround you can try to pass to installation cmd line EFI=1 which should
use correct EFI bootloader.

So reason why your booting is broken, is because it try to use legacy boot
bootloader instead of its EFI version.

Also you can check yourself if linuxrc detect EFI when you pass startshell=1 on
cmdline. Then you go to shell and check content of /etc/install.inf if it
contain line with EFI.