[Help needed] Yoga 7 (14ACN) BIOS Reflash (NVRAM replace needed)

[xiongnemo]

Hi everyone:

I came from

[Help needed] Gigabyte A5 K1 bios reflash

Hello, I unlocked the BIOS on my Gigabyte A5 K1 (it’s some Clevo barebones, as far as I can gather) using this guide: That worked fine. However, I enabled resizable BAR through the settings and now the laptop does not POST. I tried disconnecting the CMOS battery and all other power, but the laptop still does not post. I am assuming I have no other choice but to reflash the bios. I can extract the binary from the exe download on Gigabytes site, and I am in the process of getting a CH341A with…

My current situation can be seen from the bottom of that post. (There’s a limit of 2 links a new user can add to their post so sorry!)

Basically, I’m replacing NVRAM from the stock binary to the one from my chip then reflash it back.

Problem occured: After I flashed my rebuilt binary, NeoProgrammer prompted me that from some position the data could not be written, and then I found my method to replace the NVRAM was wrong:

If there is someone who can teach me how to replace it correctly it would be so much appreciated!

I used old UEFITool (UEFITool_0.28.0_win32) so I wonder whether there’s another tool that can parse and replace the NVRAM.

For the files attached:
https://file.io/KnvIzpE3eCPO

BIOS0 - stock bios extracted from lenovo (should be the latest from the fds below)
H9CN**WW.fd - fd from lenovo update package, should use https://github.com/LongSoft/InsydeImageExtractor to extract image from
nemo-tablet-14c-bios-backup-broken-nvram.bin - raw BIOS readed from the chip

[lfb6]

Please post your rebuilt binary that didn’t work.

Did you flash with a hardware programmer (CH341 for example)?

[xiongnemo]

Hi lfb6:

It’s very grateful for your reply!

This is my artifact produced in my way:

https://file.io/PX3WIKoVoGuv

Yes, I tried to flash used a CH341A & 1.8V adapter. I’ve tried flashrom and it

• can do the backup and CRC32 is correct
• failed after step1 of flashing (after reading old chip’s content)

I’m buying a new programmer and sop8 clip in case they did fail.

Edit: I even doubt whether I can successfully write onto the chip as I seen some prompt on ‘write register’ when I try to use NeoProgrammer.

[lfb6]

The replacement of NVRAM partition does look OK to me.

Can’t help you with your flashing problem, but there’s quite a lot of information in other threads regarding ‘with charger’, ‘battery removed or not’ and so on.

[xiongnemo]

Hi all:

The SOP8 clip was a crap, I got a new one and flashed without issue (flashrom under Ubuntu 22.04 LTS Live CD, 1.8V adapter, CH341A, 74M12JWSIQ)!

Problem is solved.

[lfb6]

Thanks for the feedback!