Thanks!
this morning, after sleeping a good night over it, I erased and reloaded CHDK on my flash card. No result. I was under the impression I had changed it to boot automatically.
Why?
Because when pressing <Func/set> +<Disp>, the firmware is represented as the NEW CHDK VERSION, only when putting another SD card in without CHDK, the firmware is given as the original one.
I consider this a
bug, as it puts a beginner completely on the wrong foot.
Only when I did the firmware update, way down the menu, was CHDK loaded, the splash screen showed, and the alt mode could be accessed!
Today some experiments with shutter speeds and time lapse....