Snippets of things that helped…
- downloaded EFI Studio, selected Ethernet, selected Add Device. Then clicked write to com.apple.boot.plist.
- Then went to /Library/Preferences/SystemConfiguration/apple.com.boot.plist and selected the new key and string it added.
- Then coped this string and pasted into the /Extra/apple.com.boot.plist file and saved.
Then important STEP!
- Remove all network devices from System Preferences/Network.
- Delete deleting library>preferences>system configuration> NetworkInterfaces.plist file.
* Finally, Reboot.
After reboot, go to System Preferences/Network add add devices. Click (Ethernet) FIRST!! Then add the other adapters you use to connect to the internet.