sis630 mac address

steven james pyro at
Tue Sep 24 19:19:01 CEST 2002


I don't know about other vendors, but Matsonic boards have the MAC on a
sticker just in case.


On Sun, 22 Sep 2002, Steve M. Gehlbach wrote:

> > This is probably because the MAC address in flash is 0 too. Consider a
> > flash update. You have to:
> > - write the new flash
> > - write "permanent" parameters from CMOS to flash
> >
> > then, next time CMOS gets wiped, you copy the MAC etc. from FLASH to CMOS.
> >
> > If you load linuxbios and then zero flash, boom! -- no record of the MAC
> > address of the board. If you then load the original flash, it will copy
> > the all-zero mac address to flash.
> >
> > we're going to need a way to record this kind of nonsense in FLASH images
> > of linuxbios.
> Hmm... well I never touched the original flash BIOS.  I use an EMP-30 and
> program different chips to test and run linuxbios.  I guess I thought the
> mac would be in the original bios flash, and I  guess I don't understand how
> it got changed.  The board came with the cmos jumper in the "clear"
> position, which threw me since it wouldn't come up at first until I spotted
> this.
> Anyway, the user space program to set a new MAC address in cmos is attached
> to this email; it is pretty simple, but has to run as root of course.  Maybe
> we should put this in linuxbios, as an option or something.  I wonder how
> you pick a MAC address?  At one time they were assigned in blocks by
> manufacturer, I thought.  I realize they only have to be unique on the
> subnet, but if you start assigning them randomly and shipping them to
> customers, what are the odds? Mathematically 1 in 2^48 but by Murphy
> probably 1 in 2 of a collision :-/ .
> -Steve

-------------------------steven james, director of research, linux labs
... ........ ..... ....                     230 peachtree st nw ste 701
the original linux labs                    30303
      -since 1995                    
                                   office 404.577.7747 fax 404.577.7743

More information about the coreboot mailing list