My problem is I've 4 disks in a raid array listed as sda, sdb... sdd and grub 2 refuses to boot on /sde (the 5th disk, standalone and containing a clean install of 12.04 64 bits). I tried all solutions but all fail. (live CD/USB with grub-setup, also tried repair-grub, and tried also in the "grub rescue" set prefix= etc). I also tried to deactivate the RAID array in the BIOS, but I'd rather not destroy it, and I didn't find a way to make the standalone disk as '/sda1' (this would satisfy grub). In the BIOS, the would-be /sda is the only bootable hard disk; it ends up as /sde and grubs complains. I've made repair-grub issue a pastebin. I always end up in grub-rescue and I'm stuck. I need Ubuntu to boot so that I can add the device array handler for my disks. I can't switch the disks and I can't disconnect the SATA RAID controller. I need: (a) a workaround so that grub starts on /sde; or (b) a way to change the order in which Ubuntu sees the disks, at boot time. I could then provide grub with a /sda1. Thanks a lot. up please thanks a lot it's not the same problem as booting ubuntu from raid. My RAID array serves only of data repository windows had no problem with this configuration