I tried installing Ubuntu 20.04 on an external disk (erasing the disk and install with LVM and full-disk encryption). This worked excellently; but after removing the external disk and rebooting, my old 18.04 install that is on the internal SSD failed to boot.
After some time in boot-rescue I finally got it to boot again; but I really want to try 20.04 on an external disk.
The ‘problem’ seems to come from the ‘install bootloader’ part in the install; where I picked the external disk. It seems to remove the bootloader on the internal disk.
Is this something that is expected? Or did I do something wrong?
