If the adhesive becomes hard to cut, it has most likely cooled down. Use your iOpener to reheat it.

When you slice near the front facing camera, insert only the tip of the iFlex (about 3 mm) to avoid damaging or smearing the camera.

Insert the iFlex next to the top left corner of the screen.

Slide the iFlex along the top edge of your phone to cut the remaining adhesive.

Do not try to remove the display all the way yet. The display cable is still threaded through the frame.