Aha... If I don't tell the BIOS to boot from the external drive (i.e. if I boot from my internal hard drive), I can boot the new installation on the external drive.
But only if I have it plugged in. If I don't, I get:
error: no such device: XXXXXX-XXXX-XXXX.
grub rescue>
Not sure which bits of this are intentional and which aren't. Close this bug out if it's all intentional.
Aha... If I don't tell the BIOS to boot from the external drive (i.e. if I boot from my internal hard drive), I can boot the new installation on the external drive.
But only if I have it plugged in. If I don't, I get:
error: no such device: XXXXXX-XXXX-XXXX.
grub rescue>
Not sure which bits of this are intentional and which aren't. Close this bug out if it's all intentional.