My Razr M has a problem switching from 4G to 3G. It takes forever for the phone to find the 3G signal. It can take up to 10 minutes for my data to return unless I toggle airplane mode. This also seems to happen when I leave wifi coverage. The phone seems to transition from 3G to 4G with no lag. I've performed a Factory Reset and that didn't help. I've turned off Global mode also.