When opening the rear casing be careful not to pull on the flex cables. There are 2 flex cables on each side of the rear casing.

Slightly lift the rear casing. Do not completely remove it. Just lift just enough so the right flex clamp is visible. Keep in mind the left side of the rear casing is also attached to a flex clamp. Use a spudger or other method to release the cable. Do not remove the rear casing yet.