HP Probook 5330m clean bios image request

[amarkula]

Hi,

I hope someone could help my old workhorse, HP Probook 5330m. (TL;DR need a new clean bios file)

Problem started with a brainless idea to move away from windows 8 into 10 and resulted into fiasco with corrupted bios file and password locked unbootable computer. 

About seven years back, I thought that the projects that I was working on required more security and as a result bios has password and more restricting security setting was set up.

Sadly HP was not overly co-operative and their recommended way to help, was to sell me a new motherboard with the bios-chip.

So, Now I have an bios with admin password and in an boot protected mode. I can access hard drive's Windows 8 on another computer, but I don't think it has a lot usability until I get the bios to boot. (Current BIOS is 68SFF ver. F.28)

Next thing I would like to try is to replace or reprogram bios chip.
I can desolder the chip in our hacklab and take it to my friend to be read and written. As I have no original bios file and no knowledge of which regions bios stores it's password and local settings, so putting it back would be more that crapshoot without some help. And in top of that, I have suspicion that the bios file may not have it's integrity anymore.

I have read something about bios images in these models are encrypted or at least signed or partitioned in a way that makes then unusable in their distributed form before or after being unzipped. So, any pointers on how to turn original bios upgrade into burnable image would be more that appreciated.

Any help will be appreciated.

[amarkula]

Ok, so now I have image dumped from the chip. it's size is 8 Mb.  PM me, if you like to take a look at the image.
Looks that the data from bios file has beginning at the and end tags visible on the bios image dump and is stored from 0x00500000 to 0x007FFFFF. 
(that makes exactly 314 5727 bytes)

I do wonder does direct writing to chip bypass the signature all together or should it be written into somewhere?
And are all images equal or are these rescue drives different than these normal upgrades images?