PPC64 media is not bootable on Petitboot without manual massaging
When trying to boot a stock beta5 nightly, Error loading kernel image
is shown.
This is because Petitboot has read the GRUB file as such:
Kernel: /()/kernel-ppc64
Initrd: /()/initrd-ppc64
This is wrong and prevents boot on Power8, Talos, etc.