http://www.canon.co.uk/Support/Consumer_Products/products/cameras/Digital_SLR/EOS_5D_Mark_II.aspx?faqtcmuri=tcm:14-785453&page=1&type=important
.FAQ: EOS 5D Mark II Latest firmware update
Issue
We have found the following 2 phenomena in cameras with firmware version 2.0.9.
1.Shooting stops after capturing one image when in continuous shooting or the Auto Exposure Bracketing (AEB) continuous shooting setting.
2.Misspellings in the menu screens displayed in Dutch language.
Answer :
Firmware version 2.1.1 incorporates the following fixes and improvements:
1.Fixes a phenomenon where shooting stops after capturing one image when in continuous shooting or the Auto Exposure Bracketing (AEB) continuous shooting setting.
2.Corrects misspellings in the menu screens displayed in Dutch language.
Important:
Firmware Version 2.1.1 is for cameras with firmware up to Version 2.0.9. If the camera's firmware is already version 2.1.1, it is not necessary to update the firmware.
Preparations for the firmware update:
Windows
After the downloaded compressed file (.zip) is extracted, a firmware folder is created.*Extracting the downloaded file: Right-click the zip file, and then select Extract All to extract the file.
Macintosh
After the downloaded compressed file (.dmg file) is extracted, a firmware folder is created. *Extracting the downloaded file: The downloaded folder is automatically extracted, and a firmware folder is created. If the download folder cannot be automatically extracted, double-click the folder.
The extracted folder contains the firmware (file name: 5D200211.FIR, file size: 9,754,588 bytes) and instructions on the firmware update procedures (a PDF file in five languages: Japanese, English, French, Spanish, and Simplified Chinese). Before starting the firmware update operations, please be sure to confirm the contents of the download and read through the instructions.
Firmware:
The firmware is available for Windows and Mac
No link to a download though...