When installing Ubuntu on a disk partitioned with a GUID partition table (GPT), the Ubuntu installer doesn’t set the boot flag correctly on the partitions, and on computers with older bioses (like my Intel ICH9 board), the BIOS will not recognize the disk as bootable and will refuse to start the boot loader, claiming that “No bootable device found”.
The solution is to set the boot flag on the boot partition (the real one in the GPT) as well as on the “protective MBR partition”:
- Start your computer with the Ubuntu live CD again, and select “try Ubuntu before installing”
- When the Ubuntu desktop loads, open the dash and start “gparted”
- When gparted starts, select your boot drive and from that select your boot partition – usually the first Linux partition on the drive, and right click it and select “flags” in the menu. In the flags dialog check “boot”.
- Open the dash again and start “terminal”
- In the terminal type “sudo fdisk /dev/sda” (or whatever your boot drive is). You’d get a bunch of warning about the disk using a GPT scheme – ignore them. type “a” to set the bootable flag and choose partition “1”. Finally type “w” to write out your changes.
Now its safe to reboot and your old computer should have no problem starting the boot loader now.