There is a problem with the kernel/driver/setup/wtf? that means that the second interface of the netDUO stick will not start up. The stick will puke, telling you that
# NETDEV WATCHDOG: eth1: transmit timed out Auto negotiation NOT supported
A solution is to remove the driver module and inserting it again and do a network restart. This could be done in the init.d as follows
# cat /etc/init.d/S40network
#!/bin/sh
#
# Start the network....
#
start() {
# Spider: Fix netDUO prob
echo "Fixing netDUO modules problem"
rmmod smc91x
rmmod gumstix_smc91x
modprobe smc91x
# /spider
echo "Starting network..."
/sbin/ifup -a
}
...
modprobe bridge ifconfig eth0 0.0.0.0 ifconfig eth1 0.0.0.0 brctl addbr br0 brctl addif br0 eth0 brctl addif br0 eth1 ifconfig br0 up