The Firmware Update Method allows you to load CHDK from any SD card formatted to work in your camera. It uses the camera's built-in "Firmware Update..." menu item to load CHDK from a file called either "PS.FIR" or "PS.FI2" (depending on the camera model). It is the easiest way to load CHDK but must be done each time the camera is powered on, because CHDK does not make any permanent changes to the camera when it runs.