i started getting this on router machine that worked over a year with
NetBSD-1.5.*

ep0 at isa0 port 0x300-0x30f irq 10: 3Com 3C509 Ethernet
ep0: wrote 0x7ff to TX_AVAIL_THRESH, read back 0xb450. Interface disabled
ep1 at isa0 port 0x330-0x33f irq 12: 3Com 3C509 Ethernet
ep1: address 00:60:8c:df:f8:1a, 8KB byte-wide FIFO, 5:3 Rx:Tx split
ep1: 10baseT, 10base5 (default 10baseT)

sometimes ep0 starts OK and ep1 gives such message.
if it's hardware failure, what card is broken? or maybe something else?