Be very cautious when removing the midframe. There are 2 hidden security clips on it. (My midframe broke because I did not know about the security clips when I went to pull my midframe off)

One of the clips is between your volume button and the midframe. Gently push a flathead screwdriver or a thin blade in between the frame and the volume button.

The other clip is directly in between the SIM slot and the 4 prong battery terminal. You will see a gap at the bottom of it, lightly pry it up to disengage the clip.