Using the ExMem version the JPG saved is about 800 KB filesize, of obvious very low image quality, even being set Fine quality in the Function menu. That is saving RAW or not: loading CHDK I had an 800 KB JPG filesize, not loading CHDK I had a 2-3 MB one. Changed configuration parameters, checked here and there... Even overriding quality in the Alt Menu didn't work.
Finally I've found that using Normal version instead of ExMem version solves the problem without changing anything more: just changing DISKBOOT.BIN and PS.FI2 in the root directory and using same configuration parameters. Bad news are that using Normal version the camera crashes saving DNG and going to review mode...
Guess it might be something easy to fix.
Regarding video I checked again and my camera crashes just pressing the Set button to AF during video. Anyway I don't know too much about video and video configuration, so perhaps I'm doing something wrong.