Hello, i have the same issue as jeremiah for the helix lt : i tried to update the device on the 3.10 version just after getting the helix lt and i got a blue screen while upgrading the firmware.
Since then, i have the same error : "Boot Failure, Entered Update Mode!" with the ":-3" symbol on the left of the screen.
I tried to reset the helix multiple times, change USB slots/USB cable, and re installing all the softwares, nothing really change the message.
I did all the steps above (thank you datacommando) : i can see the helix lt on the line 6 updater but when i try to update the firmware, i have this message on the line 6 updater :
"Firmware Update Failed
An error has occurred. Please try again.
Please follow these steps when updating your Line 6 Product.
1. Turn the power switch off, then back on.
2. Ensure the USB cable is connected directly to your computer and not to a hub or peripheral such as a keyboard or mouse.
3. Click 'Continue' and attempt the update again."
And this message on the helix lt : "Update failed, please reboot and try again!"
So i follow the instructions (swith off/back on, changing usb slots, USB cable, select the flash memory file 3.10 every time) but i can't really make progress since then, the update always fail maybe 1 second after i start the update. I tried with off/back on without pressing before on F6/F12 and with it. I don't have an other PC to try this unfortunately.
I'm currently on Windows 10, with the Hx edit 3.10, Line 6 updater 1.20 and the firmware 3.10 flash memory.
Thank you for your answer.