you dont need a cable. there is a usb port in the back of the starview. copy the file to a usb stick or device and insert the usb stick into the starview while switched off. turn on, press menu and select usb.
You will need null modem cable - this is for a pc though - if you are going to flash your box via laptop - unless you have a serial port you will need usb to null modem cable too. Here is a link to everything you need bud, http://forums.afterdawn.com/thread_view.cfm/663923