This step shows how to remove and transfer the power button.

Use a pair of tweezers to gently grip the power button's top rubber arm and lift it out of its slot.

Lift and remove the power button.

During reassembly, transfer the original power button to your new back cover:

Installing the power button can be very tricky and may take a few tries.

Insert the bottom rubber arm and cable together into their slot and push the button into its cutout.

Slide the upper arm into its slot.