Transfer old BIOS ubuntu to new UEFI machine?

If I install from scratch on a new UEFI machine, can I just copy everything except /boot from an older machine being replaced? Or is there BIOS and kernel related stuff somewhere outside of /boot that I'd want to avoid clobbering? (both are running 20.4). (Perhaps /etc/default or someplace like that?)

If you install Ubuntu from scratch on a new computer with UEFI firmware, you can't just copy everything except /boot from an older BIOS computer being replaced. You can actually clone an Ubuntu installation from an old BIOS computer to a new UEFI computer, but there are many different steps to follow to get the old Ubuntu that was installed in BIOS mode to work on a UEFI computer, and you should expect to encounter some unexpected problems if you are following the instructions from a tutorial. If your time is valuable there doesn't seem to be any point to doing it the hard way in this case, considering it takes only about a half hour to install Ubuntu from scratch on a new computer.

If something goes wrong when installing Ubuntu from scratch on a new computer, you can run the Boot-Repair application to troubleshoot the problem. Otherwise you're basically on your own if Ubuntu is unable to boot after cloning an Ubuntu installation from a BIOS computer to a UEFI computer, and you might have to reinstall Ubuntu anyway.