I'm testing it on b2g18 and gaia master since there seems no plan of using m-c in v1.1 for now. We should request uplifting both bugs.

To display the call forwarding state on boot, I think we can cache the state in async storage. In order to do this, an unique identifier of the ICC card is required to handle the case of users switching cards when reboot. Any better ways or suggestion on the identifier?