Just got the things4u esp8266 sketch working with the Modtronix inair9b here in US915 land, with an esp8266-03 (NOT recommended, just what I had laying around while the Wemos D1 mini is on order) - which took a bit of a hardware trick to use GPIO0&2 for DIO0&1 - namely, power on with GPIO0&2 disconnected, then plug it into DIO0&1, believe it or not that works!
Next, it looks like the LMiC library starts from a random channel 0 thru 63 (902.3 + chnl*0.2 MHz) and walks up to 63 then starts over from 0. Just stuck a horrible hack in lmic.cpp to fix it on channel 57 (913.7) - well, after the first transmission on channel 0, then update my single channel gateway and the temperature node.
Now TTN REST reports:
“data_plain”: “Hello ESP8266 world!”
Learning LoRaWAN and LMiC is going to take me a while