I am trying to boot Ubuntu 12.04 from an external SATA drive on my customer's Dell Precision M6500. I installed Ubuntu on the drive when it was connected to a USB 2.0 port on the machine. While it works there, I really want to boot it when it is connected to the USB 3.0 port on the same machine. The BIOS on this machine cannot boot a drive connected to the USB 3.0 port. We have an older Ubuntu installation on the internal hard drive and this is where my GRUB 2 boot lives. I need to be able to keep both systems available.
When I boot, Grub lists the Ubuntu 12.04 system and when I select it, I get the message, "error: no such device: 194b00ee-25d9-4b80-9b8f-d260ebb1ce41. error: no such partition. error: you need to load the kernel first."
I can boot the Ubuntu 10.0 system that is on the internal drive without any problems. I can run update-grub on that system. When I am booted into Ubuntu 10.0, I see my /dev/sdc1 device and can mount it without difficulty and my 12.04 system is there. I can use GParted and see the drive I want to boot and confirm that the UUID given in the error message matches the UUID of the partition that contains my 12.04 system. This machine already has 2 internal drives. The /dev/sda device has Windows, the /dev/sdb device has Ubuntu 10 and neither drive has enough space for another OS. I have already made sure this machine has the latest BIOS.
If I didn't care about the performance of the system, I could just plug the drive in the USB 2.0 port that has BIOS support and boot from there. However, performance is an issue and USB 3.0 is needed.
Any suggestions on how to proceed would be greatly appreciated.