Ethernet problems on Q840av

I've installed OpenBSD on a Q840av, and so far I've hit a snag with the
onboard ethernet.

dmesg comes up and identifies the interface as:

mc0 at obio0: address 08:00:07:fc:61:11

which as I understand it is normal, and shows the correct MAC address
of the card.

However once the interface comes up after logging in, ifconfig shows
its address to be all zeros. I can't ping or connect to anything, as all
other machines on my network seem to think the Quadra (IP address
192.168.0.84) is at MAC address 00:00:00:00:00:00. Ethereal  running
on my eMac while pinging the router from the 840, shows all requests
by the quadra as coming from MAC address 00:00:00etc.

I googled this message - http://news.gw.com/openbsd.mac68k/570
and found that the advice there which puts the 840av into promiscuous
mode gets everything working fine.

Is there something better I can do to make the 840av broadcast its
true MAC address so that networking works without that workaround?

thanks,
dana