[request] unlock TDP advanced options in HP spectre x360 with 8550u


I’m glad to find this forum with so much information and support.

I have a HP spectre x360 with a i7 8550u. This CPU supports a TDP up to 25 W, however it seems to be locked in this laptop at 15 W, despite my temperatures being low during a stress test and the fan being not even at full speed. This feature bottlenecks significantly my eGPU.

As far as I now the only way to increase the TDP is in BIOS. Unfortunately, these settings are hidden in my BIOS (AMI).

I found over the internet many people claiming the same problem, but no one reporting a solution.
So I would like to mod and flash the BIOS to unlock the TDP settings, and make a proper report/guide so that others with the same laptop could benefit.

But I need your expertise and guidance to do it.

1) first, is what I’m asking even possible in this laptop? is there any problem related with RSA?

2) in a first attempt I created a flashing USB drive using the HP flashing utility (083B9F24.EXE), it created a *.bin and a *.sig file (083B9.bin and 083B9.sig), then I modified the *.bin file with AMIBCP64, and I tried to flash the modified BIOS, but I get an error saying that it couldn’t open the signature file (of course, it cannot be so simple), any way to overcome this? should I use other method, such as booting in DOS and use AFUDOS to create an .rom file and then modifying and flash it?

I would appreciate very much some advice.