@arraWX you can create a Ethernet gateway in raspberry pi and connect MYScontroller to you raspberry pi gateway.
See instructions to create raspberrypi ethernet gateway on https://www.mysensors.org/build/raspberry
From there you can perform FOTA in MYScontroller.

@arraWX I find more simple to simply connect nrf24 to raspberry pi as instructed in https://www.mysensors.org/build/raspberry
But you can also build the Ethernet gateway with W5100.