Is it possible to use
update-grub to just search on specific disk/partition? (or ignore specific)?
I installed Ubuntu 12.04 on my hard drive, but i wished to do some testing on it without harming current installation, so I "rsynced" root partition (the only) to the USB partition (ext4). I did fix /etc/fstab on USB partition. The problem is that when I do
grub-install /dev/sdb (usb) GRUB seems to confuse when UUIDs. Whatever I chose in GRUB it always boot from disk. In grub in edit mode I see that in two "UUID" lines are not the same. If I retype UUID from "first" to second "line" it boots from USB (as I wish).
Is there any other way than fixing /boot/grub/grub.cfg each time?
EDIT: the GRUB generated good when I booted from USB and grub-install from there, but question is still if it's possible ignore drives