Same thing happened for me last Thursday, but used a different usb port and the update went through. My normal port stopped responding to the helix, but worked for the PC+ update. Was going out of town over the weekend for a gig, ran into a few of my go to presets that didn't work in 2.80. Reflashed the 2.80 FW with the working usb port, and it did not stall, as it did not have to totally blast the first portion of the firmware to replace 2.71. Anyway the same presets still went wonky. Ran out of time to mess with it, so I had to roll back to 2.71 and restore my backup, again with the working usb. The wonky ones on 2.80 worked again on 2.71. Got back this afternoon, and had read about folks regaining their normal usb port with a reboot of their computer, so I tried that and connected the helix to my normal usb port, and it did recognize the helix, was able to connect to it with HXEdit again, so tomorrow when I begin trouble shooting, I should be able to do the 2.80 fw update without needing to stop midstream this time. Will probably need to recreate the wonky ones, so will need to write down the snapshot controlled parameters on those, will be a pain, but at this point, no real alternatives that I see. I have another out of town gig next week end, so will have more time to dig in this time, hopefully with better results.