PTHD 10 no longer working on 2009 Mac Pro upgraded to 5,1 firmware

[mindbreathe]

Hi! I own a 3 card PTHD Accel system running PTHD v10, and I just had my 2009 (silver) Mac Pro's CPU, RAM, and video card upgraded, and the firmware of the machine was upgraded from "4,1" to "5,1". Pro Tools will no longer boot up on this machine. It gets frozen at the "Initializing Hardware (DSI)" part of the boot up process. On a new separate boot drive I installed (running Mac OS 10.8.5) I tried installing a new version of PT10 which was the version that said it was compatible with native hardware, and that still didn't work. Does anyone know if PTHD 10 is compatible with my upgraded machine, or do I now need to buy an old 4,1 firmware machine to run my Pro Tools system? Abandoning my Accel system for modern HDX hardware is financially not an option for me.

Thank you!!!
Nicholas