Canon has posted firmware v2.0.9 for the EOS 5D Mark II. It improves read/write speeds with certain CompactFlash cards, fixes Arabic, Portuguese, Spanish and Thai menu screen mistakes and addresses an instance in which lens image stabilization would not engage.
The full list of stated changes is below.
Firmware Version 2.0.9 incorporates the following improvements and fixes.
1. Improves writing/reading speeds when using UDMA 7-compatible CF cards.
2. Fixes a phenomenon where the IS function will not work when custom function C.Fn III-2 is set to [5: IS start] and the lens attached does not have an AF stop button. This is because custom function C.Fn III-2 allows users to assign IS start to the AF stop button on the lens
3. Corrects misspellings in the menu screens displayed in Arabic, Portuguese, Spanish, and Thai languages.
The update is available from the EOS 5D Mark II's Drivers & Software page on the Canon USA website.