This is done via BIOS ME Interface overrides and not directly ME Firmware…
Important is to disable iGPU and CPU Turbo, the rest is in the pudding…
Also needs a board that is build to de-couple the BLCK clock from the rest of the board…
If the board is already not capable to OC a K-Series chip BCLK beyond 105-108Mhz then don’t expect any miracles for a non-K chip either.