[OpenBIOS] l440gx+ nvram writing ...

Wallace I. Kroeker WallaceKroeker at smarttech.com
Tue Feb 8 08:12:57 CET 2000


Hello Ron,

Here is my take after reading the documentation (the documentation seems to
be identical for the 440bx).

Intel (or some other BIOS maker) write a BIOS.  This BIOS has the SMI
handler in it.  The SMI handler has a signature that it expects from the
Flash software (written by the said BIOS maker).  The signature is something
that they won't want to divulge to keep people from inadvertently
(maliciously) flashing BIOS.   

So how can you get around this?  The following steps seem logical:
	1.  Write your own BIOS that has an SMI handler with your own
signature.
	2.  Use the Flash update utility for your Board to flash your BIOS
into place
	3.  Write your own Flash update utility which supplies your
signature to your BIOS

Or the following sequence of steps:
	1.  Write your own BIOS that has an SMI handler with your own
signature.
	2.  Use LoadBios to put your BIOS in place (NOTE: you will be
redefining the SMI handler at this point to be your own)
	3.  Proceed to write your BIOS to FLASH 

Now that sounds simple enough but I suspect the tricky part is the SMI
handler.

I really don't think the signature is that magical but rather a
hand-shaking/security feature.

Wallace

> -----Original Message-----
> From:	Ronald G. Minnich [SMTP:rminnich at lanl.gov]
> Sent:	Monday, February 07, 2000 4:32 PM
> To:	openbios at elvis.informatik.uni-freiburg.de
> Subject:	Re: [OpenBIOS] l440gx+ nvram writing ...
> 
> On Mon, 7 Feb 2000, Edwin Rhodes wrote:
> 
> > Well if thats the case, lets hope to god that freedos will do the trick!
> :)
> 
> not that simple. You'll still have to solve the problem for freedos of
> unlocking the key. 
> 
> Go to intel and get doc # 245141-001 of 3/1999. Check page 19, para 2.3.2
> We need to see how that is handled. I've got requests in to Intel and
> VALinux now. We'll see how it goes.
> 
> ron
> 
> -
> To unsubscribe: send mail to majordomo at freiburg.linux.de
> with 'unsubscribe openbios' in the body of the message
-
To unsubscribe: send mail to majordomo at freiburg.linux.de
with 'unsubscribe openbios' in the body of the message



More information about the openbios mailing list