http://www.canon.co.jp/Imaging/eosdi...irmware-e.html

Q:How do I copy the downloaded firmware file to the CF card?
A:Two methods of copying the downloaded firmware file are provided.
  1. If you have a CF card reader or a PC card reader*, or a notebook type personal computer with a PC card slot*, please copy the firmware file included in the downloaded data a freshly formatted CF card.
    * If you use a CF card with a PC card reader or a PC card slot, a PC card adapter is necessary.
  2. If you do not have any of the above equipment, please connect the camera and a personal computer with a USB cable*, and copy the firmware file onto the CF card in the camera. For copying, "UploadFirmware**" (utility software) is included in the downloaded data.
    * For USB connection, the interface cable IFC-300PCU enclosed with the camera is necessary.
    ** Macintosh version of UploadFirmware requires Mac OS 9.0 to 9.2.