Canon has posted EOS 5D Mark II Firmware Version 2.0.4
"We apologize sincerely for the inconvenience caused to our customers by suspending the availability of the Version 2.0.3 firmware.
We are now introducing the Version 2.0.4 firmware. This firmware corrects the malfunction that occurred in the previous Version 2.0.3 firmware, in which the manual recording level changed and made recording impossible.
Customers who have the Version 2.0.3 firmware on their cameras should update the firmware to Version 2.0.4."
"In the Version 2.0.4 firmware, the following phenomena that occurred with the Version 2.0.3 firmware (which was to enhance the movie functions) have been corrected.
There was a phenomenon in which the manual recording settings made in C1/C2/C3 were changed and sound could not be recorded if manual sound recording was used in the C1/C2/C3 settings and the camera was subsequently turned off (or if Auto Power Off was activated). This does not occur in modes other than C1/C2/C3." (thanks John)