Hi, I am almost new to Arduino, although in the last weeks I did more or less what I wanted with it, until yesterday. I have a MKR WAN 1300, and I use the IDE on a Mac (High Sierra). After having attempted to load the LMIC library instead of the original, the serial port disappeared (I suspect due to a conflict in pins configured on LMIC, which likely is not supposed to run on a MKR. Don't ask me why I tried). I tried almost all the workarounds for missing serial ports on a Mac, with no success (change port, cable, reboot, reset PRAM). I tried the loopback test but since there is no serial, I could not do it really.
However, when powered, the Arduino remains with both leds on (green and yellow). Is this the case where I have to reload the bootloader with ArduinoISP?
Thanks for your help.