@goerdi APU2 had a bios from 2016 when it was installed.
https://community.ipfire.org/t/why-i-have-there-such-a-number-in-apu-bios/9889
I think they did not have EFI capability at that time. That came later but once a system is installed in a specific way it will stay that way unless you do a re-install.