Hello. I have the same problem.
But with MC 7455 on latest Generic Firmware.
With USB composition=9 I can Monitor Satelites with Sierra GNNS Tool. But no fix at all.
With USB composition=8 I don’t even get a NMEA Stream.
But I need also a USB Composition with MBIM because it should work in a simple way with Microsoft Maps.
I blocked some Pins to run the Card in USB Mode on the internal M2 slot.
What way I need to walk to get this running with a generic flashed Module? I also use dedicated Connector and Active GNNS Antenna. I will post a AT Output related to the Initial posting for comparing when im Home.
BTW. The Modem on the other Hand works like a charm. Fast and stable with 150/50Mbit inside a Fz-g1.
I tried to use the informations in My MC7710 can't work on Linux after plug-in it to Windows8 - #2 by rickyUm
That include a lot use full informations for the 7455 too.