Comment 7 for bug 623609

I have a patch for grub-probe on EC2.

For UEC: while there is a way to preseed install_devices to empty, if you do that then grub-install will never be run, which means that core.img will never be upgraded. I'd rather we didn't take that approach. Can you simply preseed grub-pc/install_devices to /dev/sda or /dev/vda as appropriate? grub-install seems to succeed without errors, so you shouldn't need to play any games with diversions.