I've decided to try a Verizon 4g dongle (USB551L) in my RPI. It is recognized with lsusb, and .ls /dev/ shows cdc-wdm0 and ifconfig shows WWAN0. I followed the whole guide (J-son uqmi,etc) and got no errors.
When I try network register, it says "no effect"
When I try -d /dev/cdc-wdm0 --start-network "VZWINTERNET" , it says 29031216 (This is the only thing that seems to work...I'm not sure what the number is???
but if i put something else in besides VZWINTERNET, I get "call failed"
When I try dhclient -v wwan0 it says sending on socket fallback/tries several DHCHDISCOVERS/ no DHCPOFFERS received/ no working leases