Problem verifying or clearing bios chip, while hardware flashing

BIOS/UEFI Modding BIOS Modding Guides and Problems
1

Hello everyone,

I have a Thinkpad Yoga 260, which stopped working and possibly has a corrupted bios.

My issue when flashing the bios with a ch341a is, that I am unable to verify it, regardless of what I write to it, and regardless of chip.
Whenever I write the image to a chip, reading it back I get a mismatch.
Also, when trying to clear the chip, each zero-fill cycle seems to remove more data from it, but I’m not able to get any chip to be completely filled with zeroes (FF).

I think I remember reading that the descriptor and ME regions are write protected, would that be the case, and possibly the cause of me not being able to verify it?

Thanks!

2

The Flash Descriptor locks restrict software-based flashers, not external hardware programmers like the CH341A. Make sure that the motherboard is powered-off before connecting the programmer. If it’s powered on, then there is a high chance that the SPI controller is writing data at the same time causing corruption and mismatches. If there is no power, then the programmer is not properly detecting the SPI chip.

3

I was programming the desoldered chip, and the model was detected correctly, with no errors whatsoever.

4

Then it’s definitely the programmer, usually the software can be finicky. Try the ones from the CH341A thread and some more versions/variations can be found at the replies too (even at the last page).

[Guide] Using CH341A-based programmer to flash SPI EEPROM

5

Thanks @plutomaniac , you were right. I’ve tried with a different software and now the reads and verifies are correct.