I’ve submitted a ticket, this is a widespread issue. 274 attempt to “update the headset”, fails, and when you reboot the PC the headset status LED alternates between Red, Green and Blue. Reverting to 271 and all is fine, however, SteamVR refuses to see my Tundra Trackers correctly. I am trying to use them in conjunction with Natural Locomotion and cannot assign them to feet under Devices > Trackers in SteamVR. I presume the “improved Tundra Tracker compatibility” that 274 supposedly brings.
Widespread issue with 274:
Pimax 8KX w/ 90 Hz firmware