Comment # 4 on bug 1167780 from Fabian Vogt

(In reply to Steffen Winterfeldt from comment #2)
> In theory, making LOADER_TYPE a list would do what you want but that would
> break
> basically all tooling we have around that setting.
> 
> I see no huge obstacle adding an option or environment var to pbl that
> specifies the bootlaoder to update, if that helps.

Ideally this would work automatically, so no special code just for those images
would have to be added. If "update-bootloader" is run on an EFI system it would
install grub2-efi, otherwise grub2. Not sure how that would work with YaST,
maybe a new option "grub2-auto"?