We recently saw a few cases where after updating a G10TII transmitter, it became non-operational. We believe the root cause is this:
Line 6 Updater 1.19 unexpectedly identifies G10TII devices as G10T devices. Due to this, it is possible that one could load G10T firmware 1.06 on a G10TII product.
If one ever gets into a state where they incorrectly load G10T firmware onto a G10TII, as described above, the issue can be remedied by downloading and installing the latest Line 6 Updater (version 1.20 or later – the latest version is now 1.23) and using it to re-update the G10TII back to the G10TII firmware. As of this writing, the only G10TII firmware release is the initial public firmware (2.00.0).
NOTE: If the G10TII does not appear in Line 6 Updater after a few seconds, try un-docking/re-docking the unit a few times to see if it might then be recognized.