I'd like to share a BIOS unlock method for NH55 Insyde BIOS. I got it from a chinese blogger from bilibili, don't know who actually made it. Tested with latest BIOS (1.07.08). You need format a FAT EFI partition on USB storage device to store the unpacked files and folders. Then, disable SecureBoot from BIOS menu (you must disable Secure Boot even if you can sign it with your own DB key, otherwise it will always stay at boot entry selection menu) and select the USB storage device entry on boot entry selection menu. After some seconds, you'll enter SetupUtility and see all hiden items. It'll not unlock the menu permanently since it works by modifing BIOS code loaded to RAM. If you want to enter the menu next time, you just boot the made device entry again.
After messing with options of BIOS, I found that there seems a current limit enforced by MPS drMOS controller around 128A and I can get 170W package power at most for my i7-12700 processor. Maybe it's related to temperature warning signal (VTEMP) or a value hardcoded in MPS drMOS controller profile. I checked the schematic in the service manual and found the TDC of CPU VRM is 128A. Unfortunately it's not possible to know the actually reason since code in host can not communicate with the controller, which is wired to IT5570E EC's SMBUS pins other than the host. If you want to take good advantage of the unlocked BIOS for CPU performance, you actually need a much better cooling solution anyway, I just set the PL1 and PL2 to 125W and apply a 80 ACLL for now since I don't have a unlocked CPU for voltage tuning.
NH5xJN_BIOS_Unlock.7z
