Apply a suction cup to the heated edge of the rear cover, as close to the edge as possible.

If your rear cover is badly cracked, covering it with a layer of clear packing tape may allow the suction cup to adhere. Alternatively, very strong tape may be used instead of the suction cup. If all else fails, you can superglue the suction cup to the broken cover.

Pull up on the suction cup with strong, steady force to create a gap between the rear cover and the frame.

Depending on the age of your phone, this may be difficult. If you are having trouble, apply more heat to the edge and try again.

Insert the point of an opening pick into the gap.