How do I change network configurations?

Hello everyone!

In an effort to make iMessage work, I am trying to change my network configurations so that the interface I am using will be en0 and Builtin=yes as recommended on the "How to Fix iMessage" guide.

I am using a jailbroken iPhone as a wireless adapter that shares my WiFi instead of my data because the DW1560 or others are too expensive currently.

Every time I change the NetworkInterface.plist or the preferences.plist they go back to how they were on reboot. My iPhone readjusts to en2 instead of en0.

Any way to fix this, or am I doing something completely wrong?