Have just been looking on the CHDK downloads site. I was going to download the file for my 570IS but now have another question. I know I need to download both the 1.00E and the 1.01A versions and work out which version works with my firmware, but is it best to use the Complete or Small download?? Just something else to confuse me.
Be prepared for more confusion if you continually update the CHDK file when new features are included (like the DNG file format). Sometimes, unless you are a programmer, hacker, etc., it is difficult to figure out how to do stuff, and if it seems there is a bug, and you are simply "confused", (as the manual is never updated) and you post a bug or query, be prepared for a condescending dressing down. One must always remember that this is free, and there is no CHDK for dummies manual that includes the things you want to know to use the camera underwater.
Download the full version. The small one is probably just the updates. (although I'm not sure, as there is no explanation!) Download both 101a and 101e. If your camera is fairly recent purchase, try the 101a first. If it doesn't work, then try the 101e. It's not that much of a deal to try, as soon as you update the firmware, you will get a confirmation massage telling you it is loaded. Just remember to turn the camera on in playback mode, load the firmware, change it to record mode, press the direct print button until the "Alt" message appears, and then enter the menu to set the changes (like Raw mode). If you want DNG, you will need to run a script. I finally managed to figure it out, but it took a while. After all, I'm right brained, and blond.
By the way, if you are using SDHC cards, you can't make them bootable.