powershot camera models have more or less different hardware and they need different firmware.
when a camera has more firmware versions it means that there was some bugs with the first version, the developers fixed it and they recompiled the whole firmware, so some of fuctions adressesses will change.
chdk uses fuctions from original firmware to acces sd card for example.
conclusion: if you use other chdk version than reccommended the results are mostly inpredictable but generally the camera will just hang up and you have to take out the battery
