Because it's not the update, it's just the firmware dump.
No way to convert the firmware dump to firmware update?
BTW. Did you try the existing version of CHDK in your camera? Does the camera hang with it or just reboot?
Yes, I tried the current CHDK sd700 v6 firmware. Camera just rebooted. No CHDK ALT options.
I will try to find, here in Czech Republic, some BPW96C compatible phototransistor and will try to dump my firmware 1.00B. Also, I will then ask my friend, owner of the IXUS 800 IS with the newer (european) 1.01B firmware, to borrow his camera to dump it too. I think, it could be useful for CHDK developers to be able to compare SD700 1.01B (NT) and IXUS800 1.01B (PAL) firmware dump.