Hello, I've recently correctly installed the chdk in my SD870 IS and all the options are working fine. Except the raw mode.
Even though, I'm able to activate it in the menu - it appears "Raw" written on the screen (with the number of slots I have left) - and when I take the photo the print button goes blue, the saved file has always the .jpeg format and exactly the same size of a normal .jpeg compressed photo.
I also tried changing the raw file prefix and extension but in the end I always end up with a .jpeg. I'm I missing something?
UPDATE: using the chdk file browser I noticed that my Raw files are inside 100CANON folder. Although when I open this folder using windows explorer it's empty.

Is there anything I need to do to see these files? Hmm Do I need a card reader to see them or they can also be seem by directly connecting the camera to the pc?