I just sent an email to TPCast and they sent me an package with updated drivers. So no need to buy the licens for Open TPCast. I haven't installed it yet but I'll update here if it doesn't work. Well, TPCast answered within an hour so cudos to their support!
I sent TPCast an e-mail asking if they had updated drivers for the microphone and they answered within 12 minutes with an attached file that contained the instructions. So just e-mail them :)
Problem right now is that even with the new firmware installed I get a failed system load on the power box while being able to start Steam VR but there's no microphone detected. So I'm back to square one. It works as before but no mic. I'll write again if I'm successful.