Thanks whim and waterwingz. It seems that currently only the SX220hs, SX230HS and IXUS310HS (ELPH500HS) currently have working CHDK/DE builds and are R47 - these were Feb 7th and August 23rd 2011 cameras. I see from the A2200 porting thread (reply 16) that this is DryOS R47 too. It was released on January 5th, so is it reasonable to assume that all 2011 cameras will have the capability too?