Hello, I've the same problem:
I started updating my helix lt with the line 6 Updater. But then it canceled. After this moment my helix shut down with a black screen and a red line - neither the helix lt is connected to the computer nor not.
Can you explain what you did to solve the problem a little more accurate? That would be great!
I use a windows 10 computer.
Looking forward to your awnser.
Best regards