Apply an iOpener to the center of the display, to loosen the adhesive beneath the battery.

The adhesive beneath the battery is very strong. You might need to repeat this process during the removal procedure several times. If heat does not work you can apply isopropyl alcohol (90+%) to the corners of the battery and let it penetrate the adhesive for several minutes before continuing.

The flex cables under the battery are laid out as seen in the image. Try to avoid prying in the marked areas to prevent damaging the cables.

Display flex cable

Interconnect flex cable