I just went through this myself, here is what I did. Go to the downloads section of the website and get the "Line 6 Update" app for your os. unplug your Helix from your computer, skip any USB hub and plug it right into your desktop/laptop. Restart your Helix and press the Mode + Tap buttons to get to update mode.
Does your device show up in the Line 6 Update app? If yes then use this app to update the firmware. I got this far and the update kept on failing, even when I tried going back 3 releases. I tried another USB port on my 10 yr old MacBook and it just updated, so maybe I had a less than 100% reliable USB port. But this worked for me, then I downloaded and installed the 3.11 HX Edit app and I'm up and running.
