Re: ANNOUNCE: /dev/bios - flash rom bios driver

Rogier Wolff (R.E.Wolff@BitWizard.nl)
Thu, 12 Feb 1998 09:39:53 +0100 (MET)

Dr. Werner Fink wrote:
>
> > > I can see that. But since writing the BIOS is so seldom useful, and
> > > is almost always dangerous, limiting the device interface to reading
> > > and requiring an ioctl for writing should be adequate.
> >
> > Good reason to make it a module only interface nobody loads by
> > default.
> >
> > Still its a good source reference for writing win95 bios erasing
> > viruses. Im suprised its so simple on these boxes.
> >
>
> On some (older?) boxes you have to jumper the voltage (5V -> 12V) for
> earasing the flash eeprom and to write into the flash eeprom.
>
> Flashing is just like operating on an open brain ... one mistake and
> you(r mb) will never boot anymore.

Werner,

As far as I know, the most common functionality for that jumper (on
current motherboards) is to write-protect the lower 8k of the
BIOS. That has a minimal BIOS, that can boot a floppy. This way you
can boot your "flash bios upgrade disk", if you really screw up.

The vendor SHOULD try to prevent BIOS upgrades to that lower 8k, so
that you almost never need to change that jumper, even when you are
flashing a new BIOS. In practise, however they DO change the bottom 8k
of the BIOS, requiring the jumper to be moved.

Roger. 

-- 
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