Changes in this firmware:
Firmware Version 1.2.5 incorporates the following improvements and fixes.
1. Fixed a rare phenomenon in which there were rare cases where movie files taken could not be opened when repeatedly shooting movies with specific CF cards.
2. Fixed a rare phenomenon in which there were cases where “Err 02” appeared when repeatedly shooting still images with specific CF cards.
3. Fixed a phenomenon that occurred when using high-capacity (32 GB or greater) CF cards: If either a CF card with only a little available space remaining or the battery was removed and then reinserted into the camera, and then the user attempted to start shooting movies immediately, shooting would stop.
4. Improved the writing/reading speeds when using UDMA 7-compatible CF cards.
5. Fixed a phenomenon that occurred when custom function C.Fn 4-1 was set to assign IS start to the AF stop button on the lens: When used with lenses that do not have an AF stop button, the IS function would not work.
6. Corrected some mistakes in the menu screens displayed in Arabic and Portuguese. (This applies to models in overseas markets. The models for the Japanese market do not display those languages.)
The Version 1.2.5 firmware being released this time is for cameras with firmware up to Version 1.2.4. If the camera’s firmware is already Version 1.2.5, it is not necessary to update the firmware. Note that cameras with the Version 1.2.5 firmware (and also Versions 1.2.0 through 1.2.4) cannot be downgraded to a previous firmware version (such as Version 1.1.0 or earlier).
Find both Windows and Mac versions here, at the 7D page.