Turn off the controller

Remove the battery pack or batteries

Peel off the rear grip stickers if present

Use a Torx T8 security screwdriver

Remove the five screws from the back

Keep the screws in a safe place

Separate the front and back shell carefully

Lift the shell apart slowly

Disconnect any internal ribbon cable if needed

Reassemble by aligning the shells

Reinsert and tighten the screws

Replace the battery pack or batteries