Here is a quick video clip showing the basic update process of me updating the firmware on my Icom IC-7850. The radio had the original revision firmware installed (1.00) and was upgraded to the latest (1.40) firmware. The entire process went perfectly and very smooth and only took several minutes to complete.
If you are going to do this procedure yourself, you are doing so at your own risk.

Best 73,
Len N2LEN