[LinuxBIOS] Normal vs. fallback images and CMOS

Jonathan Sturges jonathansturges at yahoo.com
Mon Oct 8 02:02:21 CEST 2007

Let me turn the CMOS question around though.  If an embedded board does have a battery, is it possible that it's just for the TOD clock and not CMOS?  In other words, if an unknown board has a battery, how can I positively confirm the existence of the CMOS?
I've got two revisions of the same board, one with battery and one without.  They're Winterminal boards, so they don't necessarily need CMOS settings.


----- Original Message ----
From: Stefan Reinauer <stepan at coresystems.de>
To: Jonathan Sturges <jonathansturges at yahoo.com>
Cc: LinuxBIOS mailing list <linuxbios at linuxbios.org>
Sent: Saturday, October 6, 2007 1:18:27 PM
Subject: Re: [LinuxBIOS] Normal vs. fallback images and CMOS

* Jonathan Sturges <jonathansturges at yahoo.com> [071006 18:04]:
> Question.  If an embedded board has no battery backup, it should have
> no (usable) CMOS.  Therefore, is a "Normal" image required on such a
> system?  My understanding is that CMOS settings are required to force
> the Fallback image to boot, except in cases of an missing or corrupt
> Normal image.

It's rather the other way around. CMOS allows the Normal image to be
booted. So without CMOS you always boot the Fallback image. Which is
good, because Fallback uses the hardcoded default values for all
otherwise CMOS drives variables.

So just drop the Normal image.


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