Need a giude how to modify Phoenix BIOS

[kroko]

Hello, everybody.
First of all I want to clarify that I am completely unfamiliar with BIOS moding and updating unless according to official procedure, so don't wonder if you find my questions strange and please, describe in details what you want to say.
I have Lenovo R61 15" 4:3, motherboard FRU 42W7822. Some of you may know that for many model as T61/R61/X61 there are modified BIOSes, based on the latest Lenovo BIOSes, that enable SATA 3.0Gb/s speed and few other things (the officials Lenovo's are limiting the speed to SATA 1.5Gb/s). These modified BIOSes also allows using Penryn CPUs (800Mhz,45nm) on motherboards which are designed for Memron CPUs (800Mhz, but 65nm) bypassing thermal sensing errors which enevedably occurs with the newer Penryn CPUs. I have updated my BIOS with the modified one and installed T9500 CPU, but the system is not able to start POST - if I push the button, the fan starts for a while, then stops and there is only a black screen. If you look at the link, under Thermal sensing colum for R61 standart screen there is n/a, which I don't know what exactly means, but I think that my problem is missing ID codes for these CPUs because:
1- Other users with the same motherboard as mine were able to load modified R61 widescreen BIOS 2.24 - 1.08 and they passed POST with Penryn CPU - here look at the bottom of the thread
2- looking at Lenovo R60/R61 standard screen Hardware Maintenace Manual, Penryn CPUs are not available for this model, but they are available for the widescreens ones.
3- if you install Penryn CPU without modified BIOS in Memron board, you will pass POST, but every time the system starts, you will see thermal sensing error message. So my black screen is another story.
That's why I think that it's missing codes for these processors, or maybe something related with the EC and I want to compare a widescreen and standard BIOS to see the differences and wether if it is missing something.
Do you think that I am right in my thoughts, or it could be something else missing in that BIOS?
There is a lot of info in the web - some old, some for UEFI Phoenix BIOSes, but I don't know where to start from, so I need some really good and complete guide for Phoenix BIOS modifications - under whinch OS, which programs to use to decompile and compile the BIOS, some guide how to easily find/compare certain sections and so on. Also, is any of you familiar with old ThinkPads' BIOS recovery procedure in case that I brick the machine?
Edit: no one with that FRU motherboard and original or modified BIOS is able to run any model Penryn CPU, so the problem is not in my CPU, it runs fine on T61!