[flashrom] JIDA CMOS

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Tue Feb 16 04:41:35 CET 2010

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?

> 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.


Developer quote of the year:
"We are juggling too many chainsaws and flaming arrows and tigers."

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