Broken Lenovo ThinkPad L420

[ijustwannaread]

Hi!

Background:
I have a Lenovo ThinkPad L420 with it's original Intel Core i5-2450M CPU that won't boot from any device (tested HDD, USB, DVD).
At startup i get 2 fast beeps with POST error message:

02F0: CPU ID: A7 No Microcode Update Loaded for Alternative Processor

The only option is to press F1 to go to BIOS settings. Looking at BIOS settings there's no supervisor password set or anything which is good.
I have another identical Lenovo L420 that's working.
To check if the CPU was broken I moved the CPU from the broken laptop to the good laptop and it worked there, so the CPU is good. The laptops have the same original Lenovo BIOS version installed 1.16 (8GET39WW).

My guess is that the broken laptop either has a corrupt BIOS or the motherboard is broken.

I identified two flash chips on the motherboard so I bought a CH341A programmer.

1. Winbond 25Q32BVSIG. I think this chip has the BIOS firmware.
   
2. Winbond 25X40BVSIG. This chip has identical checksum on both the broken and the working laptop so it's probably not the BIOS.
   

When reading the 25Q32BVSIG I got variations in data every read attempt, so I had to desolder it from the broken laptop (hopfully I can solder it back). After desolder I get clean reads everytime with the same checksum.

Request:
To fix the microcode issue at startup I want to try to re-flash the BIOS chip.

Here's the official BIOS versions for Lenovo L420.
Version 1.16 (8GET39WW) is the version currently installed but there is newer versions available for download. Newest version is 1.23 (8GET46WW). Not sure if it's relevant but the changelog mentions updated microcodes. I don't know what's the best option, sticking with 1.16 or upgrading to 1.23?

• I have attached the dump from the desoldered 25Q32BVSIG (I think it has the BIOS).
  
• See more info about the laptop in attached pictures. I used CPU-Z on the working laptop, they're identical so it should be the same on the broken laptop.
  
• BIOS info picture is from the broken laptop so serial number etc is correct.
  

I will probably only get 1 chance to flash the new BIOS and solder it back, then I gues it will be too worn out to try again.
All help is welcome

Edit: if needed I can upload the W25X40 chip dump as well.

[DeathBringer]

Try to flash BIOS dump from the good laptop to broken one.

[ijustwannaread]

Hello DeathBringer!

Thank you for your advice
I thought about doing that but then I have to desolder the chip from the good laptop and I am not sure if I can solder it back again. Then I would ruin the good laptop. I don't have much experience with soldering and don't have the perfect tools.

[ijustwannaread]

Also wouldn't it be a problem to have two laptops with identical MACs in the same LAN? I think MAC is stored in BIOS.

[ijustwannaread]

I fix the broken laptop without having to desolder the BIOS chip from the good laptop.
I checked the serial number on the motherboard of the broken laptop and downloaded a compatible BIOS firmware from the internet.

I flashed the new firmware to BIOS chip (W25Q32) while desoldered and the secondary chip (W25X40) in-place on the motherboard.
Programming software used: Colibri
Firmwares is attached.

After putting it back together and starting up the laptop I briefly got the following POST-error with 2 beeps:

ERROR 0199: System Security – Security password retry count exceeded.

Only option is to press <F1> to enter setup.

It seems to be a BIOS bug, I fixed it by following these instructions:

1) Enter BIOS setup utility
2) Press F9 to restore default settings
3) Press F10 to save settings and reboot

Maybe this will help someone with the same problem.
This thread can be closed.
Cya!