Has anyone recently built custom SkyViper firmware?

I am working on implementing avoidance algorithms for a quadcopter using ArduPilot. Since the SkyViper Journey is the cheapest ArduPilot capable drone I could find to bash around, I am using it as my starting development platform.

My question is if anyone has written, built, and uploaded custom firmware to a skyviper drone recently? The instructions to build the firmware didn’t seem to work for me. The skyviper repository hasn’t been updated since 2018 so I wasn’t sure all of the packages would still be compatible.

Hopefully someone can point me in the right direction so I don’t have to test sketchy code on a more expensive drone.

I’ve tried flashing ArduCopter stable on a Journey and it flies but I couldn’t get GPS to work (Fixtype 0) so I had to revert to stock firmware. I am investigating this issue.

I also did a Sonix build with 3 patches for mavlink cam control and system time fix from @brad112358, and mavlink port config from @chobitsfan. So far so good.

Flying now with 4.0 branch (4.0.8) with some local fixes for toy mode. (which I need to tidy up in order to send a PR).
I still could not get GPS to work on 4.1+.
So far so good.