I went to the Nikon site and downloaded the update file. It is named F-D600-V101.dmg. It is not a bin file. I transferred this file to an SD card and then placed this card in slot 1 of my D600. When I look at Firmware Version in the camera's Setup Menu, it shows the firmware status C:1.00 and L:1.006. However, there is no option to update as indicated in the instructions.
Do I need to change the file extension from dmg to bin? I'm concerned about unintentionally disabling the camera. Is there anything else I need to try to get the firmware update to proceed?