Anyways, this for when you have Intel PRO/100 VE. When you go into System Preferences/Network and your Built-In Ethernet is not show/grayed out, this is the fix for you.
You are required to add a product ID AppleIntel8255x.kext, which is located here:
/System/Library/Extensions/IONetworkingFamily.kext/Contents/PlugIns/AppleIntel8255x.kext/Contents/Info.plist
If you don't know how to get into the kext, right click it and choose "Show Package Contents."
Anyways, you will find the following line.
QUOTE
<key>IOPCIMatch</key>
<string>0x10518086 0x10508086 0x10298086 0x10308086&0xfff0ffff 0x12098086 0x12278086 0x12288086 0x12298086 0x24498086 0x24598086 0x245d8086 0x10918086 0x10608086&0xfff0ffff </string>
<string>0x10518086 0x10508086 0x10298086 0x10308086&0xfff0ffff 0x12098086 0x12278086 0x12288086 0x12298086 0x24498086 0x24598086 0x245d8086 0x10918086 0x10608086&0xfff0ffff </string>
You will have to add the following bit to the end of that line.
QUOTE
0x27dc8086
In the end, it will look like this:
QUOTE
<key>IOPCIMatch</key>
<string>0x10518086 0x10508086 0x10298086 0x10308086&0xfff0ffff 0x12098086 0x12278086 0x12288086 0x12298086 0x24498086 0x24598086 0x245d8086 0x10918086 0x10608086&0xfff0ffff 0x27dc8086</string>
<string>0x10518086 0x10508086 0x10298086 0x10308086&0xfff0ffff 0x12098086 0x12278086 0x12288086 0x12298086 0x24498086 0x24598086 0x245d8086 0x10918086 0x10608086&0xfff0ffff 0x27dc8086</string>
Save the .plist file (save it to the desktop with the name "Info.plist" and then drag it into the Contents folder for AppleIntel8255x.kext. It will ask for authentication, which you say yes to (must type password if you have one).
Open up Terminal and type in the following
QUOTE
sudo rm /System/Library/Extensions.kextcache
QUOTE
sudo kextcache -k /System/Library/Extensions
Open Disk Utility and Repair Disk Permissions.
Reboot.
Completed! Open up System Preferences/Network and you should see your Built-In Ethernet

