Hi,

After a firmware downgrade my bios was bricked. I used the tools and bios from the website, the downgrade seems to be a succes, but after a restart the screen keeps black.

I managed to follow the guide "Flash BIOS with CH341A programmer" and i managed to load the firmware back on the chip. I was not been able to use the bios from the Lenovo website because the file size was to large. However i found a bios from a member of this forum and i used that one. After the bios flash i was been able to start Windows and load the latest official bios to my system. But i found out that the bios information like s/n, MTM, and maby some other things like UUID was changed.

Before i erased the chip i made a backup. And after the last bios update i made a copy as well.

So i have 2 .bin files. One with a bricked bios but with my original information, and one with a working bios with someone else his information.

I dont have problems to edit my bios file with a hex editor. But i am a bit lost now.

1) which information form my old bios file do i need to copy to my new bios.
2) Is there a guide somewhere how i can do this?
3) Is there a tool to flash this bios to my laptop without using the CH341A programmer again, i just finished screwing back 20+ screws

My laptop is a Lenovo thinkpad Y540

Zitat von Giel538 im Beitrag #1

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1) which information form my old bios file do i need to copy to my new bios.

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Zitat von Sweet Kitten im Beitrag #2

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Zitat von Giel538 im Beitrag #1

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1) which information form my old bios file do i need to copy to my new bios.

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Module with the GUID starting with FFF12B8D-...

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This laptop will support Lenovo Variable Tool you can download it from this website.
Lvar tool can write Serial Number MTM etc very easily, i used that after having my motherboard replaced.
Hex edit is also an option but i did that on almost 10 year old laptop, so there might be some issue regarding checksum but LVar will not have any issues like that.

Zitat von SweenWolf im Beitrag #4

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This laptop will support Lenovo Variable Tool you can download it from this website.
Lvar tool can write Serial Number MTM etc very easily, i used that after having my motherboard replaced.
Hex edit is also an option but i did that on almost 10 year old laptop, so there might be some issue regarding checksum but LVar will not have any issues like that.

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This information is normally hidden in a padding, not stored in NVRAM (the GUID that was mentioned). It can often be restored from a dump of the bricked bios since these areas aren't cheanged during an update.

For LVAR there are certainly several versions, location for this information did change during the years. Did you post your dump of the bricked bios?