If I try to take a pic with the flash activated, it takes it and immediately shuts the phone off. Only way to get it back on is by pulling the battery. This plus all the weak 3G/4G and WIFI signals with slow performance issues is about to make me take this POS back any day. I dont know if its Samsung, Google or Sprint, but someone REALLY F'd up what could have a been a great phone.
I HAVE THIS EXACT SAME ISSUE WITH MY NEXUS S !! AND I FOUND THE PROBLEM: THE BATTERY , I have bought a seidio battery and using it since monday, and always when the charge is under 50%, and i take a pic with flash on the phone shut down and not opening back til i remove the battery... I tried with the factory one and there is no issue! I contacted seidio and they told me to try a couple of cycle and check out if its still doing this!
What I already tried:
Try take pic with flash on with factory battery = working
Try take pic with flash on with seidio battery at up to 80% charge = working
Try take pic with flash on with seidio battery under 50% charge = shut down!
Try take pic without flash on with seidio = working
try take pic with flash on with seidio battery but plugged to the charger = working
So definatly the 3rd party battery is the issue here and I hope it will solve after a couple of charging cycle! (Now charging my 4th cycle)