This post explains one cause of firmware updates/recoveries failing for the Line 6 POD Go. Hope this can help someone.  TLDR: prior to updating firmware, shutdown any and all applications that could conceivably use audio.  I rented a POD GO a couple of days ago, and the firmware was still at 1.40.1, so soon as I connected to POD GO Edit, it prompted me to update it to 2.0. Unfortunately the firmware update failed. POD Go Edit said it "updated successfully", but the screen on the POD GO