If "ifconfig" is used to detach a network device, the ODM is NOT updated and when the system is rebooted, the adapter will try and bring up its network interface because that is what the ODM instructs it to do.
To detach a network device and update the ODM, the following command needs to be used:
# chdev -l en0 -a state='detach'
This will detach the network device even across reboots.
chdev -l en0 -a state='detach'