In fact, since your camera uses VxWorks, you can use the 'firmware update' method to start CHDK ...
Just formatting your card in the camera is perfectly OK for this. It is only when you want to automatically
load CHDK at camera startup that a so called FAT16 partition is required, these can unfortunately
not be bigger than 4 Gb. To remedy this, the card must be partitioned, you can use 'sdminste.exe' for
this (get it by downloading Stereo Data Maker here:
StereoData Maker )
wim