This is an ancient thread, but I just got a helix in from Sweetwater. It had 3.15.0 on it. I tried doing the update and am experiencing the exact same things.
I severly doubt this is an old preset causing an issue, as the device is brand new. No amount of attempting to reinstall the firmware or any combination of holding buttons while booting has helped. I've also tried going back to 3.15.0, which the during the process of I get a bunch of errors too and then trying to update again, same thing.
I've tried multiple computers, multiple usb ports, multiple usb cables, multiple power cables, multiple power outlets, even a completely different house.
I've uninstalled everything from my computer and reinstalled just the line 6 updater. I've completely reloaded another computer so that it had the basic windows 10 and line 6 updater. Nothing has made any difference.
I've opened a ticket with Line 6, but I'm very near just sending it back to Sweetwater and ordering a headrush prime. this is ridiculous for a $1700 device.
