A peripheral device having: an interface for connection to a host device; a memory for storing software for use by the host device for operating with the peripheral device; and a processor for controlling the operation of the device such that the device has two operating modes over the interface: a first mode in which it operates as a storage device storing the said software and a second mode in which it operates as a device for providing other functionality to a device connected to it via the interface by means of the software; the peripheral device being configured so that on connection of the interface to a host device it operates in the first mode and so that it subsequently operates in the second mode.