Booting Ubuntu 13.10 from external hard disk on both uefi and bios? [closed]

Question

External Hard Disk Details, GPT, 150GB partition of Ubuntu 13.10.

Ubuntu Newbie here please be kind.

Firstly, What I would like to do is that ubuntu is able to boot in uefi computers as well as old bios based computers. I know that Uefi has a protective MBR and that can be used to make ubuntu boot on old computers. But I do not know how to get that configuration.

Secondly, I tried booting on a windows 8 computer, have set secure boot off, have made external disk a priority and have ubuntu installed in a partition still ubuntu does not boot on startup. What configuration do I need to achieve this?

Thanks a lot.

Is it even possible?

Answer 1

It's definitely possible, I have it configured in pretty much the same way (eSATA disk on which I installed Ubuntu). I had similar issues -- Ubuntu installer was booting to EFI, but was unable to create EFI partition. After installation it was trying to boot via legacy BIOS.

Long story short, I believe you have two ways -- decide, whether you are using EFI or legacy boot, pick one of them in settings and stick to it (either switch entirely to legacy mode or don't use legacy mode at all). Less confusion this way and it will ease things up during installation and dual-booting too.