I have two FMB920 units that I have set up using the backup files of two other FMB920 that are working properly. Both units when queried for ggps position return no ggps data, even when placed for more than 15-20 minutes in the open in the same positions where other FMB920 units are working properly.
The only difference I can think of between those units and the ones that the backup is from is that the SIM cards put in those have a different type of contract where only SMS traffic is enabled, but that shouldn't compromise the unit's functionality as a GPS, the SMS queries go through and get a response regularly