There is something to start with. Untested, not even put much thought into it. Try'n'error: https://github.com/armbian/build/compare/main...EvilOlaf:build:rock2f
Ignore the rpi4b stuff, accidentially mixed branches.
After a couple of weeks and more or hard work, I finished the complete overhaul of the repository. It is now handled in a much tidier way.
The result of this is a much easier support for new distributions as soon as they are published!
I have just updated the instructions, since the old repository is no longer active; I suggest you to remove the old repository from you apt sources and install the new repository as described in first page.