There are 3 main steps to perform an update.
It is extremely important to note the following to prevent problems:

1) For the first step, please double check that the firmware download you are choosing is actually for your EXACT Focal Length, Maximum Aperture, and Lens Mount of your lens.

2) At step 2 “Load Lens F/W File”, even if there is only one file present (Firmware files have a .hex extension), please double check that it is correct .hex file for your lens model.

3) At step 3” Update”, the updating process can take a couple of minutes, and must not be interrupted in any way. When updating please use a fully charged battery or AC adapter.

Do not try to remove the lens, perform other actions on your computer, or turn off your computer.

4) Do not save any firmware downloads. After performing an update, please check for any .hex or Zip files associated with this update and delete them from your computer.