my 4s is about a year old. a couple of months ago, right after i updated my iOS, it stopped charging. plugged into computer, plugged into the wall, used multiple cords to try and charge and nothing worked. then bought a Mophie for travel and found that it actually charged my phone. to this day, the only way I can charge my 4s is with my Mophie. I went to apple store and they couldn't figure it out....they used a brush to clean out the 30 pin slot and that helped for a day, but it didn't fix the real problem. any thoughts???