After the update my battery would last less than 12 hours. It was never great to begin with even new. I replaced it with this, Onite 1785 mah: http://www.amazon.com/gp/aw/d/B00CJDENDG?pc_redir=1400699206&robot_redir=1 I was skeptical about it due to the price but now for example I'm at 60% after 16.5 hours. It also comes with a torx. I've had the phone since it first came out and during that time the adhesive holding the original battery must have weakened, probably due to heat. It didn't take much to lift it out.