It's important that your Gamma Gear remains powered on during the initial content update. If it turns off at some point, it could stop working properly.
If your power was interrupted while performing the update and you are running into issues with your Gamma Gear, please first ensure that it has a fresh set of batteries, then perform a factory restore.
Once you've done that, you will have to play through the introduction with J.A.R.V.I.S. and complete your first mission with Iron Man, then re-register with the AvengersNet App; at that point you will be prompted to download the update.