UPDATE]: G2 head tracking with Vive Tracker (No Input Emulator, all native in SteamVR) : r/HPReverb
Valve index HMD error 108. Headset is on idle mode (blue) won't detect on steam vr. when I turn off direct display mode the headset will display my screen and turn green but still won't detect on steam vr. Anyone got a fix? : r/ValveIndex
Fix Error 108 Headset Not Detected when using Steam VR - YouTube
The Most Common HTC Vive Problems, and How to Fix Them | Digital Trends
HTC Vive not detected: error 108 in Ubuntu 18.04 · Issue #156 · ValveSoftware/SteamVR-for-Linux · GitHub