Currently, there is only one possible solution to this problem. We've tried it and it worked. Basically, all you need to do is change the network mode from 'global' to 'LTE/CDMA' so the device wouldn't be stuck in global GSM, which doesn't support 4G. Here's how to do it:
1. From the Home screen, tap the Menu key.
2. Choose Settings.
3. Tap More Networks.
4. Go to Mobile Networks.
5. Now choose LTE/CDMA by touching it.
In our case, we weren't receiving any 4G signal after the update at all. And NO, Factory Reset CANNOT solve this problem. We know, we already tried it. It was only after we changed the network mode that we were able to get 3 bars of signal (we used to have full). So, basically, Verizon has to look into this matter because there is really a problem with the new firmware.