How can I reset the NVRAM inside a full dump of an AMI Aptio BIOS file?


I have an Intel Atom Z3536F powered Chinese tablet and touching some of the settings in the BIOS (AMI Aptio, but not sure if it’s V or IV), which I thought they were harmless (shame on me), I bricked my tablet. Now it’s unbootable. So I think if I do a full dump of my non working BIOS, reset the NVRAM settings and flash it again, I’ll bring back to life the tablet. Currently I bought the programmer and a SOIC clip and they’re on their way here, so I don’t have right now the full dump of the BIOS, but I want to be prepared about what I should search in the dump. I have no clue about what to do and it’s what I’m asking for to all the experts here.

There’s an update from the manufacturer, but unfortunately is not a full dump. The tablet has Gigadevice 26LQ64 8-pin chip, which sports 8 Megabytes, but the update is just 4 Megabytes.

For references, I’ve found a thread here where other person asked the same but for an Insyde BIOS:
How to reset NVRAM on Insyde Bios (brick recovery Aspire Nitro)

I’ll appreciate all the help I receive. Thanks.

@ rezt:
Welcome at Win-RAID Forum!

Have you already done a look into >this< thread?
Anyway I hope, that you will get some help from a BIOS repairing expert.

Good luck!
Dieter (alias Fernando)

Thanks, Fernando!

Yes, I saw it before posting here. That’s what I’m going to do but with a flash programmer I bought, instead of a raspberry pi.

My plan is similar to what these guys did:…-hdmi-tv-stick/

But I need a working BIOS to do the job… It will be better if I manage to modify my BIOS, instead of waiting for someone with a programmer (I’m not sure if AFUWIN will do a full correct BIOS dump in this case) to extract a working BIOS from the same tablet (a combination very hard to find: people with the same tablet, electronic skills and a flash programmer).

Well, it seems that AFUWIN only gives a partial dump after all. A good friend managed to bring me a BIOS dump made with it and comparing it with the official update of this tablet, I couldn’t pinpoint the NVRAM region since there are lot of differences between them.

When I dump my non-working BIOS, I’ll do the comparison again… but I’m not very hopeful about it.

I know this is an old thread, but I found my way here via Google and thought I’d share some info.
The BIOS should conform to the platform initialization spec. What you are probably interested in is covered in volume 3. Specifically, the information is about firmware volumes (FVs). Your particular BIOS probably has a special firmware volume for the NVRAM variables. But there is no spec on how variables stores are actually implemented. I think there used to be tools to decompose a ROM image into component FVs and that should be able to help you ID the section you are after.

@splynncryth :

Welcome at Win-RAID Forum and thanks for your contribution!
I hope, that you will get a reply to your other 4 posts regarding different topics.

Dieter (alias Fernando)