Additional tweaks include a manual volume adjustment (as opposed to the automatic gain the cameras usually employ), a brightness or RGB histogram display (this function, like some of these other features, has been available for a while as a hack), shutter and aperture priority modes have been added for movie shooting, and the audio sampling ramp has been bumped from 44.1KHz to 48KHz.
ENGADGET: Canon EOS 5D Mark II firmware 2.0.3 arrives at last to free us from frame rate hell