Likely it's dead sorry. You may recall that in Post #171 i said: "It may be a hardware failure, most likely a faulty flash chip to display that kind of behavior however it's much more likely to be a software bricking. That opinion is because simply the coincidence of your friend updating with GarminExpress and simultaneously having a hardware failure is unlikely. Therefore it's far more likely to be a 'soft' than a 'hard' bricking so let's run that to ground first". I'd leave the battery disconnected for longer, even a couple of hours although usually 5 minutes is enough to drain any residual charge.