However, I don't think I'm even there yet since the error I'm receiving in the NbDmiFit script indicates I'm missing the necessary HPyyxxxx.exe file (If I understand the process correctly). I see references in this thread to unlocking the MPM, but I'm unfamiliar with that term so I assume I haven't done that.
I have tried making a bootable FreeDOS USB drive and copied over the contents of NbDmiFit versions 2.09, 2.10, and 2.13 (each version was a separate attempt), all resulting in the same error message: 'Vendor code not supported in this package' This is my first go-around with an HP hardware issue of this nature, but I am a systems engineer by trade, so I'm not afraid of poking around. Going through the BIOS, I can see the SKU and Serial Number are still intact and I have the CT number recorded on a sticker inside the OEM case. I own an HP ENVY 750 that randomly lost its System Board CT Number. If I need to create a separate post, or post in another thread/area, please just let me know. I am struggling, but I feel this thread has information I need to put me on the right track.