Firmware Version 1.5.1 incorporates the following fix.
1. Fixes an issue that in rare instances, the camera may become inoperable when shooting in the Servo AF setting while operating the <af-on> button. </af-on>
Canon always appreciates user feedback on our products and services. Following the release of Firmware Version 1.5.0, in addition to this Version 1.5.1, we are in the process of developing an update to further optimize AF operations. We plan to publish details of the revised firmware in late March and will make an announcement on the Web site.
Firmware Version 1.5.1 is for cameras with firmware up to Version 1.5.0. If the camera's firmware is already Version 1.5.1, it is not necessary to update the firmware.
Preparations for the Firmware Update:
In the folder you downloaded are the firmware ( EOSR5151.FIR / file size: XX,XXX,XXX 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 check the procedure in accordance with the instruction.
Firmware download link: