Questions about LinuxBIOS

[steven james]

Greetings,

The unfortunate thing about most BIOS recovery jumpers is that they are
simple GPIO inputs, meaning the boot block has to read a regisetr and
decide what to do. Naturally, that means that the boot block must not be
the part that needs recovery.

They COULD have that jumper actually toggle an address so that a true
backup boot block is used, but they don't. To make matters worse, some of
those same boards have a chipset with that feature built in, but that is
left unconnected and the rescue jumper is wired to GPIO instead.
</soapbox>

G'day,
sjames


-------------------------steven james, director of research, linux labs
... ........ ..... ....                    230 peachtree st nw ste 2701
the original linux labs                             atlanta.ga.us 30303
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On Thu, 13 Nov 2003, Adam Nielsen wrote:

> Thanks for your reply, it was most helpful!
>
> > Yes. A variety of NICs can be used with Etherboot as your payload.
>
> Oh good, I was hoping that would be the case ;-)
>
> You mention booting Windows 2000 on the web site, does this mean it would be
> possible to boot other OSes such as DOS?  It seems that it would be possible,
> except that a lot of BIOS calls DOS uses haven't been implemented yet - if
> these were implemented, would that be enough to boot DOS?
>
> > > One of the motherboards has a recovery jumper
> > No, the recovery jumper will program some factory presets into a factory
> > BIOS. It does not act as a recovery BIOS.
>
> Are you sure?  I'm not talking about the CMOS reset jumper - all the docs I've
> read about this feature say that can be used to recover from a failed flash
> attempt, as it contains the bare minimum code needed to boot a floppy (which
> then courtesy of AUTOEXEC.BAT runs the flash program.)  The docs say to wait
> for a certain series of beeps to indicate the flash was successful (as there
> is no video.)  From this description it seems that if I have a properly
> configured disk handy, then should the new LinuxBIOS decide not to work, I
> should be able to recover by reflashing my original BIOS.  When I last tried
> enabling the jumper, as soon as the motherboard powered up it started reading
> the floppy drive, continously (as I had no disk in there) until it was
> powered off again.
>
> The only thing I remember reading was something about the BIOS boot block
> never being overwritten during an upgrade, so if the LinuxBIOS flash
> procedure does overwrite the boot block I guess this procedure wouldn't work.
>
> And for what it's worth, I've only ever seen this on Intel motherboards (which
> have soldered flash chips.)
>
> > Oh, then disregard what I said about getting a backup. Unless you switch
> > projects and get a board with a removable ROM, of course :)
>
> I actually have two boards, and one of them does have a removable ROM so
> that's ok ;-)  It actually seems to be quite similar to the Gigabyte GA-6BXC,
> which it seems you used to use (I have one of these boards too, but not for
> fiddling with ;-))
>
> > Can you provide some more details about this specific board? Knowing the
> > north/south bridge chipset would be most helpful in case Ron has easy
> > answers for you.
>
> Yes, I didn't want to bombard you with too much stuff the first time ;-)
>
> Board 1: Unknown brand, P6LX-A+.
>
> According to the manual it has an "Intel 82440LX (PAC)" and an "Intel 82371AB
> (PIIX4)".  It's running a Celeron 300A at the moment.  Googling for "P6LX-A+"
> is where I found most of the info.  I haven't seen any references to 440LX,
> but I'm somewhat hopeful on the PIIX4...  This board has a pretty standard
> socketed BIOS chip (seems the same physically as the GA-6BXC.)
>
> Board 2: Intel, unknown model.
>
> This is definitely an Intel board (looks like an Intel, has an Intel AA model
> number [AA 666761-205], etc.) but according to Intel it doesn't exist - I
> think that's because it's sold through Gateway - the BIOS comes up with a
> "Gateway 2000" logo, and the only info I could find was on Gateway's website.
> Information on the board itself is a little sketchy but it seems fairly
> modern for its time - it's only a P133, but it's ATX and uses SDRAM.
> Googling for "MBDSAC071AAWW" gives a little info about it.  I can't find a
> manual, so I'll just list some of the larger chips I can see... ;-)
>
> Intel PCIset SB82437VX
> Intel PCIset SB82371SB
> Intel E28F002 \n BCT80 \n U7050566D (this is the surface mounted flash chip)
> SMC FDC37C932FR
>
> Hopefully that's enough for you to tell me there's no support for this one
> yet ;-)
>
> Thanks,
> Adam.
>
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