Yes, that is a feature of the flash chip, actually. Some flashes,
called 'Boot Block Flash' or similar, have a dedicated area in the top
or bottom (the top is right for i386) of the flash array which have a
dedicated physical write protect line.
> When I've had to upgrade my BIOS, the official dos-program said it
> wanted to write to the "dangerous" part, and required me to move the
> jumper.
It is very simple, the flash program just compares the boot block with
the corresponding part of the file it is asked to program and asks the
user to move the jumper if they differ.
Since every flash that I've seen jag be identified by software ant the
boot block have a fixed size and location for a particular type of
device, this behavior could be implemented in the flash programming
driver if it hasn't already.
/Daniel
-- Daniel Engström - Lilla Fabriken AB - Technical Support daniel@lillfab.se - Work related. 5116@telia.com - Private.
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