Every issue of Ubuntu LTS since 8.04, I have made a Full install of Ubuntu to USB flash drive, and recorded each step. Ubuntu installation method has changed since those days.
This has been intended to make a guide/check list for users wishing to create Full install Ubuntu family bootable drives that ares up to date for each generation.
For 22.04 these instructions should work for both creating and running the drive booted from either BIOS or UEFI.
The question is:
How to Create a Full Install of Ubuntu 22.04 to USB device with Step by Step instructions that work in either BIOS or UEFI.
Creating a Full Install of Ubuntu 22.04 to USB that works in both BIOS and UEFI
Following is based on using a 16GB Target drive, you may adjust partition sizes for a larger drive.
The following looks like a long procedure but it should take less than ten minutes to do the work.
Note 1: Problems
If there are any problems booting, first try re-installing GRUB:
sudo mount /dev/sdx3 /mnt
sudo grub-install --boot-directory=/mnt/boot /dev/sdx
Next, if there is an efi entry in fstab, # it out.
Note 2: Hard drive removal.
Note 3: Apple compatibility.
Note 4: Encryption (optional).