Anybody?? Some details, if it will help. The battery is a 2400mAh Mugen battery, and I am more than a 100 percent sure it is causing the problem. Does anybody like a video of what is happening maybe? But heres what I just tried: I taped the SIM in place, put in the extended battery, it took longer than usual to power up, then asked me to confirm the settings (this only comes up when I put in this battery), and then it started going from No Sim symbol, to 3g connectivity, back to No Sim, and sometimes just No signal! I replaced back my original battery, and it hasnt failed since. I have tried this test so many times, so the battery is the problem. And the fact that taping the SIM in place didnt matter, means (to me) that it is not the pressure the battery is putting on the SIM (meaning this is not an external problem, it seems). Any thoughts/suggestions?