I've a bit of sad history with CHDK. In 2010 I installed it on my G9. It bricked the camera. It would only take completely black fotos. I took the camera to the authorised repair shop in Berlin and they replaced the main board for 150Euro.
Bricking a G9 with CHDK seems unlikely as thousands of CHDK users have not had such issues. Obviously something happened. It may or may not have been related to CHDK = a random hardware failure while you happened to be using CHDK for example.
When I got it back it took me too long to realise that all fotos are now overexposed by 1 to 2 apertures.
Mechanically, the camera is fine. So, this appears to be a software issue. My question is now: Can I use CHDK to permanently change the exposure settings?
CHDK does not make any permanent changes to your camera. However, when CHDK is running, it can override picture settings. Unfortunately for you, these overrides force fixed values of shutter speed, aperature and ISO sensitivity rather than offsets (like adjust exposre 2 stops relative to what the camera thinks it should be). To do that, a new feature would need to be added to the CHDK core code.
Alternatively, you could use a script to do this but that would mean you have to do all your shooting by going into <ALT> mode and activating the script.
Given that I damaged the camera on my first attempts with CHDK I'm a bit reluctant to simply try.
As I said at the start, the risk is low. But you have to decide how you feel about that - if you can use the camera without CHDK and are nervous it might be best to leave it alone?
