Comment 18 for bug 436340

I struck the same problem with the 19 October daily build of karmic-alternate-amd64.iso (I didn't try the livecd.)

During the installation, grub2 (grub-pc) was installed - not grub - and failed to detect the dmraid devices as above.

Booting into rescue mode. Was asked if I wanted to initialise the SATA raid devices (yes), but received the error "The installer could not find any partitions"; it found the existing partitions during the installation process. Opened a shell; dmraid and /dev/mapper were configured correctly. Set up the chroot environment, removed grub-pc and installed grub.

I eventually got grub to install correctly, but running update-grub created the menu.lst file with an extra comma on each of the root device definitions e.g. "(hd0,2,)". Script bug? (I tried to report it via ubuntu-bug, but it fails with it's own bug!)