Unable to execute DEVINIT by PMU

There is a custom laptop. I made it myself. I went through a bunch of different video cards, from TU117 to GM107. Only GM107 is working. Falcon is not in HS mode there, and I can change devinit and dcb for the video card to work correctly. The others don’t allow me to make changes in devinit. How do I sign a modified devinit? Or switch the PMU to non-secured mode? Moderators, please call the engineers, I really need to solve this problem. I’ve been banging my head against the wall for months. The documentation says that you can disable it to run unsigned microcode, but not a word about how to do it!