I encountered a similar (perhaps the same) issue during beta testing. The update stopped midway, as I was expecting, and then stalled. Helix Rack would not reboot, and the Updater program would no longer recognize it when connected (i.e. it was not 'enumerating' in Line 6 Updater). Here's the advice I received from Line 6 at that time, and it worked for me:   .... if it is not enumerating in Line 6 Updater you may want to try to put it into manual update mode and see if it enumerates.
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