So, can you tell me if you can successfully retrieve the current DR, using modem.getDataRate() ?
Yes, I can. But I have updated firmware and library; did you?
But being not connected, it stills returning -1.
I do not understand what you mean. Is the node communicating with the gateway (by the way, real gateway or single channel?). If you have issues with OTAA, try ABP first.
modem.begin(YOUR_PLAN);modem.DataRate(xx); // -> Returns OK!modem.getDataRate(); // -> Returns -1if (modem.joinOTAA(appEui, appKey)) modem.getDataRate(); // -> Returns OK