A storage device includes a plurality of expanders connected to a disk device and a controller unit for controlling the expanders. The disk device stores data transmitted from a host device. The controller determines whether, when download data is received from a predetermined terminal to update firmware of an expander, it is necessary to initialize a corresponding expander after downloading the download data by the expander, transmits determined initialization determining information determined to the terminal, transmits the download data to the corresponding expander, and instructs the corresponding expander to update the firmware at a timing for updating the firmware, which is determined by the terminal based on the initialization determining information.