I need a method of creating a Full install USB that boots both BIOS and UEFI.
Full install USB's have advantages over Persistent USB's as shown here: Running live usb on 2 different PC's
I want to be able to carry my customized Ubuntu 20.04 OS around with me and boot it off any x86-64 computer that meets Ubuntu minimum spec's.
I have seen a few methods of creating a Full install USB, but they are either not simple or do not boot BIOS and UEFI. The use of an image file seems like the best method.