Canon has released a minor firmware update for the EOS-1D X Mark III. Firmware version 1.6.2 incorporates the following fixes:
1. Fixes an issue that, in rare cases, displays an Error Code 70 after
the camera has been connected to a network for a prolonged period of
time.
2. Fixes minor issues.
If the camera's firmware is already version 1.6.2, it is not necessary to install the update.
You can download the firmware from the Canon UK website.
After the downloaded compressed file (.dmg file) is extracted, a firmware folder is created. This should happen automatically. If the download folder cannot be automatically extracted,
double-click the folder.
In the folder you downloaded are the
firmware fil (1DX30162.FIR / file size: 65,844,240 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.