I have a Gigabyte X85A-UD3R motherboard with an ICH10R. I also have a RAID 0 (striping) setup of 2x1TB disks, configured at the BIOS level (raid controler which boots before OS/after BIOS?) which merges the two physical volumes into one 2TB volume labelled MainVolume. The volume contains four primary partitions - two for Windows (boot and data) and two for Linux (root and swap), no logical partitions.

I had problems installing any Ubuntu after 10.04 on this setup. In fact, I installed 12.04 by installing 10.04 first and then upgrading. Ubuntu 10.04 worked flawlessly, but after upgrade to 12.04 it always displayed a message during boot in the console, something like "iwatch dm-5 failed" (not sure), but I didn't pay much attention to it because the system worked. Up until today's upgrade to 12.10.

Today when I upgraded to 12.10 at the end of the upgrade process it tried to install grub, and failed with the message:

Path `/boot/grub' is not readable by GRUB on boot. Installation is impossible. Aborting. 

Then the upgrade manager offered me to select a destination for GRUB - sda, sdb or MainVolume. When I select MainVolume it falls back to the above error message and asks again. I didn't choose sda or sdb, because I thought it might write to the physical drives as non-striped and mess up existing partitions. In the end I chose not to install grub and completed the upgrade.

I'm writing this now from that box which I don't dare to reboot since it might not boot.

:(

Any ideas & sugesstions?