A method and system for customizing a mobile host device is disclosed. An accessory device for interfacing with and customizing a mobile host device includes a communication channel designed to establish a bi-directional communication link between the accessory device and the host device. The accessory device also includes a processor communicatively coupled to the communication channel. The processor is designed to execute a plurality of applications. In addition, the accessory device includes an input assembly communicatively coupled to the processor. The input assembly is designed to minimize a total number of input elements included in the input assembly. Further, at least a first input element being selectively mapped to one or more input functions of the host device based on a user selection.