Owners can find instructions for removing the HTC One's battery on iFixit, Unlike some Android phones, the HTC One's battery was not designed to be replaced by owners.
The aluminum back of the HTC One doesn't have a cover, so users need to remove the screen to access the phone's interior. Even after taking off the screen, which requires specialized tools, users need to disassemble a number of interior components to reach the battery. The battery itself has an adhesive to keep it in place. Replacing the battery also requires removing the copper shielding around the motherboard, which can be difficult to position correctly during reassembly.