Yes, even the old CHDK did that job nicely on my old IXUS 100 IS. A script for this (and adaptive exposure stacking, very useful for unlit roman interiors when

Yes, even the old CHDK did that job nicely on my old IXUS 100 IS. A script for this (and adaptive exposure stacking, very useful for unlit roman interiors when you're looking out a window with bright sunlight) came with the download back then. And at least for CHDK, there wasn't actually any flashing. It just used the firmware flashing mode as a bootloader.