Sorry to bump an old thread but i'm having the same issue as OP - got an HP DV6-6B51EA which also has a dead AMD gpu which black screens when driver added. I've tried the BIOS attached on page 3 but the machine won't even start with this one - it also appears to be 4.5MB whereas my original dumped BIOS from the chip (read with MiniPro Programmer) is only 4MB. Machine with the bios from page 3 turns on for a second then off again. I attach my dumped stock bios from the machine.

@sagael - What do you need?

@crc2018 - What BIOS are you trying on page #3? It looks like 38, 41 are for sure all working, and #40 BIOS working or not results posted at #47 - All should be 4MB, so of course anything that is 4.5MB would not be valid and may be stock BIOS extracted that's posted for some other reason (ie you can't program this in)
You do not have same exact system as OP @jeroenvtec so I am not sure if you should even be able to use this BIOS, what is difference between 6C12ED and 6B51EA?

Please explain, after you read this thread, and you have same issue, what do you need me to do to your above attached and known working BIOS?

@Lost_N_BIOS I tried the bios on post #41 which is 4.5mb when extracted.
The exact issue i'm having is that whenever I install the driver for the AMD GPU the screen goes black when it switches to it - integrated Intel GPU works fine. I need a BIOS which will allow me to turn off the PCIE GPU and just use the onboard integrated Intel GPU. If that can be done to my good known working BIOS would be great!

I know the SKU's of the laptops are slightly different but from research it looks like the same motherboard is fitted to both - same CPU generation and GPU.

@crc2018 - That BIOS was made by @jeroenvtec and is stock edited BIOS, which contains BIOS itself and several other images all encrypted it must be flashed with the stock extracted flash package, not programmed in.
Additionally that is BIOS region only, so even once decrypted cannot be programmed in. You will need to choose another BIOS here if your system is not running now.
If you want a proper fixed BIOS for your exact model, please link me to your BIOS download page, and give me dump of your bricked chip contents from BEFORE you tried to write anything with the programmer.

The issue you describe is dead/dying AMD card, this has nothing to do with BIOS. If your system is not bricked, and you just need settings change as you mentioned, dump the chip and send me the BIOS I will make that change for you
Or, you could just remove the graphics card, unless it's part of the main board PCB?

the bios you downloaded is indeed the encrypted one, I attach the non encrypted one. ( after a while searching I believe I found it :))
@Lost_N_BIOS the bios does not fix the the gpu issue but with it you can disable it so you still can use the laptop normally

@Lost_N_BIOS Unfortunately the GPU is soldered to the board and not removable. The file I attached in first post was a dump of the bricked chip contents before I wrote anything to it. I can restore this BIOS to the chip which will restore the system back to the state it was in before. If that one can be modified to have the option to turn off the PCIE GPU would be good. If not the latest BIOS for the machine is available at https://ftp.hp.com/pub/softpaq/sp59501-60000/sp59755.exe

@jeroenvtec
Thanks for that one but that is also not 4MB exactly - it's 4.06mb and a DEC file type? My original dump is 4096KB or 4MB Exactly.

Is there anything stopping me from using the encrypted one and flashing it from within windows using the stock HP flasher?

ah dec file is decrypted so ready for use with external programmer, a decrypted one you have to flash with the inside tools.
I see I have also 4096 dumps, with what did you made the dump ? I have to look further in my saved data of this project. sorry

edit
its the uefi image

@jeroenvtec - I can try that one certainly i'm using a MiniPro Programmer. TL866A I believe it is.

@jeroenvtec - nope it's the same with the other file you linked - it programs ok but machine wont even power up with it - power light flashes for a second then off

Reprogrammed the original bios dump i took which has restored it back to working state - obviously i still have the gpu issue but now the system starts and posts again!

I'll put my hands up i'm more of a hardware person than a BIOS mod person! But I am wondering if I pulled the enable signal off the buck converters for the PCIE GPU whether the machine would actually still post or it's going to hang waiting for it. Might be a better solution if it works than the BIOS mod as then GPU won't be powered creating heat for no reason!

Further update to this - I went ahead and hardware modded the GPU power supply off - if anyone comes across this issue in the future and wants a permanent fix i'll write what you must do below:
Locate R1035 (next to PU803) and PR824 (Next to PU804) Both are near the GPU chip itself - your looking for 2 8 pin mosfet IC's (PU803 and PU804). Remove both R1035 and PR824 - after you do this reset the CMOS and then start the machine up boot into windows and install the normal intel IGP graphics driver - you'll see that the AMD card is no longer powered or detected at all.