Gents, I had the exact same problem and saw your post yesterday. While waiting for someone to reply, I ended up resolving it myself.
I can't say this is the ONLY solution, but I was able to connect my Helix and eventually get past with the update mode through Line 6 Updater.
Unlike doing it through HX Edit, Line 6 Updater recognized my Helix without any "connection interrupted" messages, and I let it run through the update successfully.
I think it's a bit silly that Line6 website makes a big deal out of people needing to follow the instructions carefully - yet I haven't seen any official post on this simple troubleshooting to save people's time and frustration.
I hope this works for you, too.
