[lubuntu] grub2 on powerpc(32) G4

hi, I installed , from minimal-iso, lubuntu-Quantal and grub2-common ...

then I run:update-grub2

and it find kernel and initrd

then I run:grub-install /dev/sda

but I have error
what can I do?
strange is that in /boot/grub I have only 2 files: grub.cfg e grubenv



thank you