I have had the same problem, even though the unit worked fine initially. For a variety of reasons, I hardly used it for 3 mos. so it is sadly out of the simple return period.
I'll open a support ticket but until this is resolved I'll have to go back to my trusty shure - and this does make me leery of future failures. It's a shame because it seems pretty great at first, except for the problematic USB power connection, which others have already mentioned.
If line6 is reading this, I'll mention that the line6 updater I just tried does not have access to any firmware update (1.04 is referenced in the pinned notes).