I also had the problem were grub chose the wrong root (hdx,y) for all partitions.
** Changed in: grub (Ubuntu) Status: Unconfirmed => Confirmed -- GRUB's menu.lst modified in wrong way -> Error 15 File not found on next reboot https://launchpad.net/bugs/61108 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs