Seems like a pretty common problem on Linux. I use Unity for development and basically just have to hope that it works on the different Linux distributions (I'm not a Linux user myself). I tried to search around for more info on this issue but I couldn't really find much. Hopefully some Linux guru will be able to chime in.

Here's one thing a found:

"Had the same issue on two other Unity-games. There is a simple workaround that worked for those games and might work [..]

- You need to callibrate (move the analogs around) before starting the game.

Just do a couple of circles with the analog sticks before starting the game and it should be fine.
As i understand it it's a bug with Unity's controller library under Linux."

After some research, as someone mentioned, some buttons must be emulated otherwise the controller is not recognised by FPVfreerider.

To do that, use the wejoy : https://github.com/Vantskruv/w... and calibrate the original joystick with jscal to get rid of deadzone. Then FPVfreerider is working like a charm!