US Patent 9092233 Accessory booting over USB

Methods, systems, and apparatuses for booting an accessory with an accessory firmware image received from a host device are described. When the host device detects a connection between the accessory and the host device, the host device may send a request for an accessory identifier to the accessory. The accessory may send an accessory identifier to the host device in response. The host device may select an accessory firmware image that is suitable for the accessory, and may transmit the accessory firmware image to the accessory. The accessory firmware image may include information that the accessory can use to enable the accessory to exchange application data with the host device.