The trouble here seems to be that remote and box need to be set together (or at least, that is all that the help describes) and setting the box back to #1, and then going to #2 with the new remote, will leave the original remote stuck on #1 again 😢
I think there is a simple two-part question here:-
“I have a Humax Freesat box that I have set to Remode Mode #2, with its existing remote.
I have a new additional remote for it, which does not control it, as it is, I expect, on Remote Mode #1.
How do I get this remote onto Remote Mode #2 and still have the original remote and the box on #2?”
which you could perhaps usefully ask on:-
https://myhumax.org/forum/topic/programming-remote/
as someone there may know the procedure for it.