I got the same problem here using two SATA disks without any RAID configuration. Had to revert the entries using the live cd all times the updater reverts to uuids.
-- LVM/MD root filesystem not found by uuid https://launchpad.net/bugs/54002 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
