I'm trying integrate a GPRS modem in Android 6.0.1 without sucess. Modem works well at hardware level and answer correctly AT commands. In Android UI I only see SIM card not present and not related do modem works.
In Android log I can see a lot of subId=-2, phoneId=-1, slotId=-1, I think my problem is because of this wrong numbers.
Someone with experience in Android RIL could help me to understand how this numbers are generate and where?