My FC is working just fine but I was reading the manual for my Radiance and it states when using it with the Frsky XSR (which I am) to use this CLI command: set sbus_inversion = OFF. When mine is set to ON it works just fine but when I follow the manual and set it to OFF I can no longer arm my quad. As I said before, mine is working just fine so this is more a curiosity than anything and hopefully it will answer someones question down the road.

So, what does the Sbus Inversion on/off command do exactly?

FrSky receivers send their signal inverted - a high signal level means zero and a low signal level means one which is the opposite of how a serial signal would normally work.

sbus_inversion tells the flight controller how to interpret the signal.

Gotcha. Thank you for that. I did get my XSR used so I'm guessing it was changed on the RX at some point so that having the Inversion set to ON on my FC it would work fine. It just seemed odd that the FC manual would tell me to set it to OFF but if it works then it works.

It's far from uncommon for flight controller manuals to be wrong.

All FrSky S-Bus receivers send an inverted signal, so I have no idea why they would put that in their manual.

I think Furious changed the serial inversion on their boards at some point so inconsistency happens between different batches.