Good evening,
I spent some time for testing. My setting:
Both cards are enabled in sim card settings.
The network seletcion is in auto mode
Roaming enabled
I tried all protocol settings Dual / IP / IPv6
The result always the same:
The sim card which is selected for mobile data was able to register to the network, the other one turns after searching into unregistered…
I can receive calls only with the sim card which is set for mobile data. I can not receive calls on the sim card which is seleted for calls only and not for data. ("Number not available ") Making phone calls was not possible with the sim selected for calls (and no mobile data) → no network message…
Maybe it is a Swiss specific issue…