The back cover of the HTC Evo 4G protects the swappable battery and the included 2GB microSD card. To access either component, you can remove the cover without any tools. It’s strongly recommended to power off the phone before removing the battery cover to prevent data loss.
Removing the Battery Cover
Small clips secure the battery cover to the smartphone. Inserting your fingernail in the slot at the top left of the cover gives you a grip on it. By gently pulling away from the phone, the hidden clips release with an audible snap and the cover detaches.