Last week I replaced the LCD, Battery and the back case of my 16gb white iPhone 3g. Afterwards I couldn't get it to turn on. For some unthinkable reason, it never even crossed my mind to troubleshoot the phone myself. I took it downtown (Mexico City) and a guy plugged it in and upgraded the phone to stock 3.1.2 without asking me.

The phone worked just fine, except that now it is locked to AT&T (a major pain in my ass). Also, the wifi works, but only if I am within ten feet of the router. Before, I could be in any part of my apartment and have no troubles connecting.

Any ideas? I know I'm screwed as far as the unlock goes, but without phone OR wifi, this thing is pretty useless.