peter is not talking about CMOS. He's talking about saving  data in the flash ROM that is tied to an individual motherboard. Those are very different things. 

Here's a simple example from older systems. They would save the ethernet MAC in flash. When you did an upgrade, you had to use the existing flash as input, else your MAC would be lost or appear as all zeros. You can imagine how tricky this can be if the exist flash rom has, e.g., GPIO settings that must be transferred to the new flash image before flashing.

Hence, just a raw factory image may not work. 

We really need to start warning people when the flash a thinkpad that it is very important to save the old flash image.

ron

On Thu, Feb 2, 2017 at 11:52 AM Zoran Stojsavljevic <zoran.stojsavljevic@gmail.com> wrote:
> I think that will be a problem. Lenovo BIOSes save some machine-specific
> information in the flash ROM across updates, and I've so far not seen
> a single Lenovo mainboard which does not require this information for
> the vendor BIOS to work.

Let say, you are right/correct, Peter. Then I need explanation for this text:
http://www.howtogeek.com/131623/how-to-clear-your-computers-cmos-to-reset-bios-settings/

Reseat the CMOS Battery

If your motherboard does not have a CLEAR CMOS jumper, you can often clear its CMOS settings by removing the CMOS battery and replacing it. The CMOS battery provides power used to save the BIOS settings – this is how your computer knows how much time has passed even when it’s been powered-off for a while – so removing the battery will remove the source of power and clear the settings.

Important Note: Not all motherboards have removable CMOS batteries. If the battery won’t come loose, don’t force it.

First, ensure the computer is powered off and you’re grounded so you won’t damage the motherboard with static electricity. Locate the round, flat, silver battery on the motherboard and carefully remove it. Wait five minutes before reseating the battery.

Since I am kind of naive, and do not understand what these people are talking about (you are opposing them, am I correct, or maybe not)?

> It's a kind offer, but not useful in my experience, for the above reasons. All Lenovo BIOS updates require a Lenovo BIOS.

Two questions/conclusions: did you ever try what I proposed here? If NOT, it is worth trying. If YES, total valid observation. Then DEDIPROG flash programmer or similar of kind is a must, unfortunately?!

Zoran


On Thu, Feb 2, 2017 at 8:53 PM, Peter Stuge <peter@stuge.se> wrote:
Michal Widlok wrote:
> Ron - I've lost original bios, my mistake.

I think that will be a problem. Lenovo BIOSes save some machine-specific
information in the flash ROM across updates, and I've so far not seen
a single Lenovo mainboard which does not require this information for
the vendor BIOS to work.


> On Wed, Feb 1, 2017 at 9:20 PM, Zoran Stojsavljevic <zoran.stojsavljevic@gmail.com> wrote:
> > I'll try to find the original BIOS for Michael

It's a kind offer, but not useful in my experience, for the above
reasons. All Lenovo BIOS updates I've seen so far require a Lenovo BIOS.


//Peter

--
coreboot mailing list: coreboot@coreboot.org
https://www.coreboot.org/mailman/listinfo/coreboot

--
coreboot mailing list: coreboot@coreboot.org
https://www.coreboot.org/mailman/listinfo/coreboot