Some good news, managed to get the camera to load the CHDk firmware and blink an LED with it.
Found out the correct dancing bit encoding code (0,4,2,7,3,6,5,1), luckily was already in CHDK code, so auto booting with a lock SD card already works.
Next I'll try to make the booting sequence work (at leas to get a screen on). Once that works I'll publish the code somewhere.