Canon Camera Hackers Manual page 24

15
3.5 The warranty question
The camera is obviously designed to load and execute software found on
the card—the situation is similar to fitting a third-party lens to a DSLR.
The CHDK alters neither the camera nor the camera's firmware in any
way. Reformat the card (or use a fresh card), and the CHDK is gone. The
camera continues to run under its original firmware. In fact, before sending
in the camera for warranty, you should remove any memory cards from the
camera. A camera equipped with a CHDK-enabled card may disturb service
technicians and make their job difficult. In addition, the card may also
contain images that you don't want to share with others.