[Renate]

Well, I'm glad that you're not disheartened, we're almost there.

Your boot image is in Android image header format #2.
Not being aware of this I lopped off the DTB and Magisk didn't notice.
Give me a couple of hours to write some new code and then write a test.

Until then, don't bother doing anything.
Except a copy of that long.img would be appreciated. Thanks, got them.

Also, if originally B was active, was the edl.exe /g indicating it the other way around?
Did the relabelling of the partitions not occur when there was a swap?
Another mystery.