Lenovo IdeaPad 730S-13IWL, RMA board with Invalid fields, bios recovery

BIOS/UEFI Modding BIOS Modding Guides and Problems
1

Hi guys, I’m new to the forum. I found this site after having a bad experience with my laptop.

A few years ago, my laptop got damaged during a storm—the motherboard got fried. Recently, I found a cheap RMA replacement from Lenovo. It arrived a couple of days ago, I installed it, and it worked. While I was in the BIOS changing the boot order, I noticed that values like Product Name, MTM, and Lenovo Serial Number were missing—they showed up as “INVALID.” My first thought was, “maybe updating the BIOS will fix it.”

So, I flashed the latest version from Lenovo’s website. The board originally came with BIOS version 8HCN35WW, and I updated it to 40WW. The flashing process went fine, but after it rebooted automatically, it no longer POSTs. The screen stays black, and the Caps Lock light turns on, but nothing else happens.

At that point, I started looking for the BIOS version it originally had, thinking maybe the newer version has some issue I’m not aware of, and tried to go back to it. I put the BIOS file on a USB with various names and tried different key combos like Fn + R to trigger a recovery flash, but nothing worked.

Today, I learned about a programmer with a clip—CH341A—that lets you reflash the BIOS without desoldering it. I’ve ordered one to try flashing the 35WW version I found online. It’s in .CAP format, but I extracted the .bin file using UEFITOOL_NE by pulling out this GUID: 6C60EE00-C316-4C95-A684-CDC7E7033311.

I’d really appreciate your opinions on what might have gone wrong and whether this approach could actually work. I still don’t understand why the board won’t boot with the new BIOS. Could those INVALID fields have something to do with it?

Also, I’ve read here about the Lenovo Variable Tool. Is that the right tool to modify those missing values? Or is there a way to just inject them directly into the .bin file before flashing it with the programmer?

Thanks and cheers!

2

That mboard came out from Lenovo RMA or private seller “as an RMA past purchase”… the 1rst time updating the bios, the setup usually asks if we want to update motherboard/system data…
Is there any backup or the possibility to read the IC of the old motherboard to retrieve system original data? These are some operations that should be done with the SPI programmer when arrives.

3

When I updated the BIOS, the program didn’t ask me for any information, it just restarted and a DOS-style screen appeared to perform the update. Once it finished, it rebooted and stayed stuck there with black screen.

I still have the old board that got fried at home, so I believe I could retrieve the data if the BIOS chip is still intact. What operations would you recommend I take? I’d like to have a clearer idea of what to do before I receive the programmer.

Thanks!

4

Yes…since this is a consumer laptop it may skip the data inquiry, it’s more common on business systems.
What operations… nothing for now without a programmer.
That CAP file you programmed earlier was a full spi fw image with all regions, because if it’s only a bios region update file from Lenovo, it won’t work.

EDIT: You need a full image of 16348Kb.
Read both ICs of both boards and share the dumps if you want, a final fw image from/with must be reconstructed.

1 Like
5

I’ve re-downloaded the BIOS I updated from the website https://download.lenovo.com/consumer/mobiles/8hcn40ww.exe, extracted the .cap from the .exe using Innoextract, and opened it with UEFITOOL_NE. I don’t know much about this topic, but from what I’m reading and seeing, it looks like it only contains the BIOS region and is missing the rest of the regions. On the same Lenovo website where I downloaded it, there’s another separate file that is the ME.

Well… I don’t understand why Lenovo provides this file without it being complete. I’m assuming that updating only one region causes some kind of incompatibility with the others that aren’t updated. Maybe I’m saying something dumb, but the solution would be either to flash the BIOS region again to version 35WW, which I had previously, or to flash a complete SPI firmware, either from another board by reading it with a programmer or downloading one from the internet.

Thanks for helping me understand the issue.

6

I confirm that the one from Lenovo’s website is not complete, the .cap file is 13,422 KB in size.

Can you recommend any guide or post to learn that can help me to rebuild it? I have a few days off until the programmer arrives and I like to learn.

I have no problem sharing the dump if it makes things easier, much appreciated. Can someone misuse it?

Regards and thanks!

7

Already told you what is needed in my last post.
You may try to use the image from old system board or edit/swapp regions/volumes in failed updated RMA fw image.
Every system board has unique data id and mac adress, this needs to be edited as also the corrupted sections if trying to use RMA board image recover.
Its not an easy task and consumes time, there’s no guide for it, as is not always the same procedure/steps, this is skills acquired and gained experience.
There’s several Lenovo bios recover threads in the forum, i do suggest to learn something from them.

In the end an image like this, is whats needed to be programmed.

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image748×395 15.7 KB