When you upgrade a SBC from one release to the next using the dnf upgrade method, it
updates all the files in the filesystem in the same way as with a standard installation -
I guess. So it would be fine to use that method on a SBC installed by
arm-image-installer.
But what about the files idbloader.img and u-boot.itb which arm-image-installer copies to
the boot media in a separate dd step? Does the dnf method upgrades those, too, or do I
have to do it manually afterwards? Or is there something else to do?