I reported a MAC address of all zeros on my laptop (SiS 630
chipset). After inspection of the FreeBSD, OpenBSD and Linux drivers, I've
submitted a patch (PR#14655). This reads the MAC address correctly (stored
in CMOS not in EEPROM on the SiS 630 chipset). However, problems still
remain:

- media autodetect does not work (interface is dead until
  ifconfig sip0 media 10baseT)
- When using NFS, I get a lot of:
  sip0: transmit FIFO underrun; increasing Tx drain threshold to xxx bytes
- After a few increases in the Tx drain threshold, I get truncated-ip
  errors in tcpdump. At this point NFS completely hangs.

-- 
Stephen