[flashrom] JIDA CMOS

Marc Ferland marc at mferland.net
Tue Feb 16 18:09:12 CET 2010

At Tue, 16 Feb 2010 04:41:35 +0100,
Carl-Daniel Hailfinger wrote:
> Hi Marc,
> On 15.02.2010 18:00, Marc Ferland wrote:
> > I work with kontron based COM boards. We currently use their home (DOS)
> > tools fptup and jidacmos to update the bios of our boards.
> >   
> Kontron developers contributed to flashrom in the past, and AFAIK they
> are using a slightly modified flashrom version inhouse which can do
> incremental writes. Mainline flashrom is now catching up with that (we
> had to convert drivers for >200 chips first, and that took more time
> than we had hoped).
> > flashrom [...] works for updating
> > the BIOS image, but doesn't seem to be able to update the
> > configuration part of the BIOS. The result is an updated BIOS version
> > with a wrong configuration (which fails to boot correctly).
> >
> > Searching a little deeper, I found that to succesfully update the BIOS
> > on these boards, you not only have to update the BIOS image but you
> > also need to "pre-configure" it correctly. This is done by executing
> > the jidacmos DOS utility using the following cmds:
> >
> > jidacmos rtc /clean
> > jidacmos eep /clean
> >   
> Just to make sure I understand you correctly: Do you run jidacmos before
> or after the BIOS update? And does it touch the BIOS update file or the
> flash chip or the NVRAM?
I run jidacmos after the BIOS update, and no the BIOS isn't updated.

> > So my question is: 
> > What is this jidacmos utility? Kontron doesn't give much details about it.
> >
> > You guys have any idea of how I could reproduce the behaviour of the
> > jidacmos utility (cleaning the rtc and EEPROM I suppose)?
> >   
> Heh. EEPROM and CMOS are probably the most abused terms for a piece of
> computer hardware that's called NVRAM nowadays. On some modern machines,
> the term EEPROM actually is correct because there's no NVRAM anymore and
> firmware/BIOS stores everything in the flash chip (saves a few cents).
> nvramtool may be useful for your task (which looks like clearing NVRAM),
> but if there is no NVRAM in your machine, editing the BIOS image before
> flashing may be the way to go.
I've continued my search, and it looks like a JIDA32 kernel driver
exits along with a jidacmos utility for linux. I wonder why I didn't
see that before!

From the readme.txt:
The jidacmos linux tool enables you to save and restore the CMOS settings of
all supported Kontron CPU boards from within a Linux environment.

I'll also take a look at nvramtool.

Thanks for your time,


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