I got the expected "Boot Failure. Entered Update Mode!" message halfway through the 2.80 Firmware update on my Helix LT. I pressed OK on the Updater, and nothing seems to be happening. It's been stuck at 50% and the Boot Failure message for about 45 minutes now.
I was watching Glenn Deluane's video on the 2.80 update, and his seems to get passed the Boot Failure message and back to "Updating Helix Firmware" pretty quickly.