Yes there is another thread on the Troodon boards about no firmware beyond 3.0 working correctly giving driver errors etc. I have no idea why. We don't make the Troodon boards and don't know what or how it's been changed. You'd have to ask them about that. But 3.0 does appear to work.
You may be able to use USB and Bossa software to flash the 3.0 firmware directly. See if you can work your way through the fall back update procedures.
https://duet3d.dozuki.com/Wiki/Installing_and_Updating_Firmware#Section_Fallback_procedure_Num_1