Apple changed the Ethernet adapter in all new Mac mini's6,x (at least 6,1 & 6,2) to BCM57766, the tg3 drive in base will no longer work with these new devices :|
Broadcom has an updated Tigon tg3.ko driver v 3.124c with many enhancements over the older version which is in the latest Linux kernel, but not 3.0.21.
I have compiled a driver using corepure in text mode and made an extension, works great once the old tg3 is removed and the new tg3 modprobe'd
Assuming this is the right way to accomplish the task, Just need to write a start-up script to run
sudo modprobe -r tg3
sudo modprobe tg3
sudo /opt/eth0.sh
Unless there is a better way