Canon has removed the firmware 2.0.3 from their home page due to complains about audio not being recorded in C modes.
Important Update Information for Firmware Update Version 2.0.3
We recently 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 EOS 5D Mark II digital SLR 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. For customers who have already downloaded and updated to Firmware Update Version 2.0.3, when using the camera with the mode dial set to C1/C2/C3, please set the Sound Recording settings to Auto to record with audio.
We are currently preparing a new firmware that will correct this malfunction and have temporarily disabled the ability to download the current firmware until the issue can be resolved. We will re-enable the download link on our web site and notify you via e-mail when it becomes available. If you have not registered your EOS 5D Mark II, please register so we will be able to notify you.
Canon always strives to provide the highest quality products to our customers. We sincerely apologize for any inconvenience this may have caused. We appreciate your kind patronage and support.
Let's hope it comes soon. Another flop from Canon :(
You can follow what users been talking and complaining about this update at the Fred Miranda Forum.