Looked at the TH9800.py chirp driver for a start. Guessing it has a lot of similarities to the 7800. I used the 9800 driver a template, changed a few obvious things, and tried to get a dump. Unfortunately it didn't work yet, but there are lots more things I can try.
Any pointers on how to "sniff" the dump from the TYT software? I saw what looked like a dump that someone posted. Not sure if it matches what my radio is doing or not. I used something like "serial splitter" on Windows a long time ago for something similar. Not really a Windows guy, but can go there if I need to. The TYT software is Windows only.