I just discovered that when I tried to replace a 3g screen with a non 3g device screen.
The comments do not show up yours should be on by default.
Excellent instructions. Fixed my camera, flash and proximity sensor. due to ribbon cable that joins the sub board to the main board. as soon as I pulled the board apart the ribbon cable header just fell out of its socket. You need to add remove the other ribbon cables as well otherwise some novice may inadvertently damage the connectors.