Stephen,
There is an article on the knowledge base that will guide you on the firmware update via USB only. You will need to contact Technical Support to have the serial firmware file emailed to you. The process and update file are different. You also want to ensure that the ActivDriver is up to date. What version do you have?
To update the firmware via USB, the article and file are located at www.prometheankb.com, select your region/language, in the search box type in 10360. To contact Technical Support via the web form on the knowledge base at www.prometheankb.com, select your region/language, Interactive Displays, Contact Us.
In the Existing case field input case number: 269534.
Thanks!