What a mess…it took over 6 months to produce and due to lack of testers I assume…Canon have had to suspend the new 5D2 firmware because of sound issues. I don’t know what they are but I will update you as soon as I know.

Canon respond…
Recently we have discovered a malfunction that occurs with Firmware Version 2.0.3, in which the manual recording levels for C1/C2/C3 are changed and the camera becomes unable to record audio if the power is turned off (or if Auto power off takes effect) after registering “Sound Recording: Manual” in the camera user settings.
We apologize very sincerely for the inconvenience, but we are going to stop making this firmware available for download. For customers who have already updated to the new firmware, when using the camera with the mode dial set to C1/C2/C3, please either set the sound recording settings to Auto.
We are currently preparing firmware that will correct this malfunction. As soon as those preparations have been completed, we will let you know on this Web site. In the meantime, we apologize for the inconvenience this represents, but please wait until the fixed firmware is ready.