Re: Intel Pentium Bug

[hudson () MBAY NET (Stefan Hudson)]

On Fri, Nov 07, 1997 at 07:35:48PM -0500, Kragen "Skewed" Sitaker wrote:
> If Intel releases code to update the microcode, someone else will figure
> out how to do it, too.  That means we can look forward to a future of
> microcode back-doors and viruses.  (How big is the microcode on a Pentium,
> I wonder?)

I'd imagine that there would be some sort of hardware access to the
chip required to do this; for example, putting the chip in a special
motherboard that puts programming voltage on a certain pin.  Laptops
with integrated processors might have a jumper or solder pad that
could be used to apply the voltage.  A special instruction would then
be used to put the chip in programming mode and upload the new code.
A higher than normal voltage would be required anyway if the code was
stored in EEPROM type memory, I believe.

This would make the microcode patch a lot more complicated, but it's
still better than shipping it back to Intel for replacement, and it
eliminates any possibility of "unintended" microcode updates.  They
said it was upgradable; I don't think they ever said it was
SOFTWARE upgradable.

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