Re: Flash linux into PC bios?

Peter Horton (pdh@colonel-panic.com)
Thu, 22 Apr 1999 00:36:38 +0100 (GMT)


On 19 Apr 1999 thospel@mail.dma.be wrote:

>
> In article <Pine.LNX.4.04.9904172013390.649-100000@berserk.demon.co.uk>,
> Peter Horton <pdh@colonel-panic.com> writes:
> > On Sat, 17 Apr 1999, Paul Jakma wrote:
> >
> >> theoretical question:
> >>
> >> what would happen if i flashed a linux kernel into the BIOS of a
> >> recent pc motherboard, given that the EEPROM is big enough to hold
> >> the kernel.
> >>
> >> would it work. the kernel already can initialise most motherboard
> >> chipsets, eg PIIX, VP3, so how much stuff does the bios do that the
> >> kernel can't? is there any really low level stuff that needs to be
> >> tweaked, eg memory timings, that linux couldn't do?
>
> As a data-point, I once screwed up the bios on an ASUS P2H4 motherboard,
> and tried to boot linux when all the system could still do was starting a
> boot floppy.
>
> The boot worked succesfully until it had to really read something from the
> IDE-harddisk. At that point it failed completely. I did some extra experiments
> with forced geometries in lilo, but to no avail.
>
> Still, I was already quite far into the boot, and I suspect that if the IDE
> initialization could be done without the BIOS, it would in fact have worked.
>
> (since it got a bit boring, a flashed a working BIOS again :-) )

This is unlikely to be a usable solution. The problem is the crisis
recovery mode of the BIOS is required only to run a very basic DOS setup
and a re-Flashing program. This means there is no requirement for all the
memory to be setup (or to be setup for best performance), for the caches
to be turned on, or for the CPU to be run at it's normal speed. If you
have a PCI/AGP video card, it may not even be initialised. The boot block
might only be 8/16K in size, and this means the boot block BIOS is cut
down to the very bare essentials to do crisis recovery.

Shame though as this would otherwise be quite cool ...

P.

---
+---------------------------------------------------------------+
|  Peter Horton     -    software engineer    -     Linux 2.2.6 |
+---------------------------+-----------------------------------+
|  pdh@berserk.demon.co.uk  |  http://www.berserk.demon.co.uk   |
|  pdh@colonel-panic.com    |  http://www.colonel-panic.com     |
+---------------------------+-----------------------------------+

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