Sorry, next time, I'll search more before asking lol
CHDK can't boot on SDCARD more than 4GB.
I've read this page :
http://chdk.wikia.com/wiki/Bootable_SD_cardand it is working now !
One more question :I've tried Custom AUTO ISO.
I guess that the parameters of this function are REAL ISO ?
But why the shutter speed when pressing half the shutter button is not the real speed ?
(for example, on screen I can see 1/8 and the real shutting could be 10 seconds !!)
The EXIF also does not reflect the AUTO ISO, but the canon's values on the screen.
I have also noticed that Custom AUTO ISO is not working in AUTO MODE With FLASH.
In P MODE, it works.
.