If the phone's rear glass is cracked, the suction cup may not stick. Try lifting it with strong tape, or superglue the suction cup in place and allow it to cure so you can proceed.

Secure a suction handle to the lower edge of the rear glass, as close to the edge as possible.

Lift the rear glass with the suction cup to create a small gap between the glass and the frame.

Insert an opening pick into the gap.

If you have trouble, apply more heat to further soften the adhesive. Follow the iOpener instructions to avoid overheating.

Slide the opening pick to the bottom right corner.