In a terminal device and a method for controlling charging, a first processor controls an adapter to charge terminal device when the terminal device is connected to the adapter. The method includes receiving trigger information by the first processor; turning on a first communication interface according to the trigger information by the first processor; acquiring a firmware update file of the firmware from a server by a second processor; transmitting the firmware update file to the first processor via the first communication interface by the second processor; and updating the firmware according to the firmware update file by the first processor.