Hi Fredrik,
On Sat, May 17, 2008 at 05:48:49AM +0200, Fredrik Tolf wrote:
This mail is justa noteworthy observation I've made. I've got two separate M57SLI-S4 motherboards on which I've installed Coreboot, and I've noticed an interesting thing with the onboard Ethernet chip. It seems it contains one MAC address in hardware,
It's in software - it's in the bios image.
which is changed by the factory-shipped BIOS during boot. The hardwired address begins with 00-E0-81, which seems to be registered to Tyan[1], and the address which it is replaced with begins with 00-1D-7D, which seems to be registered to Gigabyte. This is noteworthy for two reasons:
- It confused me a lot at first. Since udev assigns a new interface
name for every MAC address it discovers, it made my DHCP client fail since it couldn't find the interface it was configured for, so at first I thought that Coreboot couldn't initialize the NIC. I got past that pretty quickly, though.
- More importantly, the hardwired address is actually the same for both
motherboards! More precisely, it is 00-E0-81-54-32-66. Thus, running several of these board on the same physical link is a bad idea if one does not change the address manually.
I don't know if anything should (or can) be done about this in Coreboot. I just thought I'd mention it.
Try the attached script to update the mac address of your image prior to burning it.
This should really be documented on the wiki. It applies to (almost) all our mcp55-based boards.
Thanks, Ward.