Hi, I am posting this in the hopes that someone else might find this answer who is experiencing this issue. I was trying to update my new Line6 Firehawk's firmware, I had the Firehawk attached to my computer via USB cable, I had downloaded the Line6 Updater software and installed it and ran it. However, in the software, it did not show the Firehawk. I tried two different computers, and two different USB cables, all with the same result.
It turned out that Line6 devices will not appear in the updater until you have registered them with Line6. Once I registered it with Line6, it appeared.