Accessing the internals of the 4th generation Shuffle is extremely difficult, as the rear panel is both glued to the front case and secured by metal retaining clips. It is highly unlikely that you will be able to remove the rear panel without inflicting cosmetic and/or structural damage.

Before proceeding, be sure your Shuffle is switched off.

Use a combination of iPod opening tools and metal spudgers to pry the rear panel away from the Shuffle by the seam nearest the ON/OFF switch.

Remove the rear panel from the Shuffle.

If present, remove the thin black moisture seal covering the Shuffle's internals.

Remove the single 2.1 mm Phillips screw securing the logic board to the front case.

Use the edge of an iPod opening tool to flip up the retaining flap on the control button cable ZIF socket.

Be sure you are prying up on the hinged retaining flap, not the socket itself.

Use a pair of tweezers to gently pull the control button ribbon cable out of its socket.

Use an iPod opening tool to gently pry the battery off the adhesive securing it to the front case.

Lift the battery out of the front case, being sure not to strain its delicate leads.

Insert the tip of a metal probe into the hole molded into the logic board retainer nearest the logic board.

Pry the retainer first away from the front of the front case, then pull it away from the side of the front case.

Remove the logic board retainer from the Shuffle.

Use the edge of an iPod opening tool to push the headphone jack down toward the center of the Shuffle.