I've got the IXUS 255 camera on hands. Since it looks like there was no big efforts on its porting yet, would like to initiate this process.
I've dumped the camera FW using cbasic, it resides here: http://www.sendspace.com/file/lm5ztq
FW version is 100f (ACID 1.14).
The respective string resource in FW states that it is "DRYOS version 2.3, release #0052".
If I understood site materials correctly, the main action chain would look like:
1) Find the most compatible CHDK port
2) Find using finsig/cb scripts/disassembly all basic memory addresses required to just start CHDK
3) Check and adopt one by one all the functions required by CHDK
I plan to move deeper in July, since currently have lot of other things to do. So, any help or guidance is welcome.