I'm a user of supermicro X8DT3-LN4F. It features Intel 82576 with 4 LAN ports.
The AppleIGB Kext works well in Mountain Lion but after upgrade to Mavericks 10.9.5 I got the same problem that some users have :
it never ends.
When my system boots, Chamelon detects my LAN ports well, the leds are working but when OSX Launches, the driver just turns off the connection (lights stops binking on the lan port). The system still boots and I can see my 4 ports in the network interfaces panel but none is able to connect and lights are still off.
After editing the Chameleon org.chameleon.Boot.plist I added the id of my intel 82576 to the system. I found it with some software and the system recognized it, but still same problem with no connection. It just changed the status "integrated lan" to YES in system info software and change the names of lan ports in the System preferences->Network but nothing better. The best status i got was the orange color says : this network adapter have a self assigned IP. Then, maybe there is a solution to use the AppleIGB from mountain lion because it was working fine... but I didn't succeed in doing that.
If someone has some clues it will be very helpful, because my system with mountain lion isn't optimal and I found with Mavericks 10.9.5 it's faster and more stable, my only problem is this LAN problem...
Thank you very much for your help.