Your iPhone 4 rear cover may have either two #000 Phillips screws or Apple's 5-Point "Pentalobe" screws (second image). Check which screws you have, and ensure you also have the correct screwdriver in order to remove them.

Remove the two 3.6 mm Pentalobe or Phillips #000 screws next to the dock connector.

During reassembly, we recommend you replace the 5-point screws with equivalent Phillips screws. Our Liberation Kit provides the tools and screws needed to replace the Pentalobe screws with Phillips screws.

Push the rear panel toward the top edge of the iPhone.

The panel will move about 2 mm.

Pinch the rear panel with your fingers and lift it away from the iPhone.

Remove the single 2.5 mm Phillips screw securing the battery connector to the logic board.

• Some devices may have two screws, one of which holds down the contact pad which is located above the screw indicated in red in the photo.

Use a plastic opening tool to gently disconnect the battery connector from its socket.

Use the clear plastic pull tab to gently lift the battery out of the iPhone.

Be careful when removing the battery with the plastic pull tab. On some units, Apple uses an excessive amount of glue, making it virtually impossible to remove the battery in this fashion (with the tab possibly tearing due to excessive force).

For batteries that "stick", you could use the iPod opening tool to assist (take extra care whilst doing so).

You might find it easier to pry the battery out from the right-hand side because no glue is used on this side.

Remove the battery.

Before reconnecting the battery connector, be sure the pressure contact (shown in red) is properly positioned next to the battery connector.

Before reassembly, be sure to clean all metal-to-metal contact points on the pressure contact as well as its contact point on the rear panel with a de-greaser such as Windex (96% ethanol alcohol works well too, but make sure that contacts are dry when done). The oils on your fingers have the potential to cause wireless interference issues.