I modified MyConfig.h file and RFM69 driver to allow you build gateway (ethernet or MQTT) with W5100 ethernet and RFM69 radio modules using SoftSPI bus. You can find it at: https://github.com/gieemek/RFM69_softSPI-for-MySensors-2.1.1
@MiKa
Hi.
oki, in case i'll add some explanation.. I'll be busy for this week but you can simply use the serial gw example from MySensors for getting started, this should work. I didn't need to create a special board in arduino for this board, so if you're using it, you'll need to install&use the mattairtech SAMD21 board definition for the pin mapping.
https://github.com/mattairtech/ArduinoCore-samd
