WiFi.ping(ip) freezes mkr1000 if WiFiUdp.h included in project. to show problem - open standard sample WIFI Ping after #include <WiFi101.h> add #include <WiFiUdp.h> upload to mkr1000 tested with firmware versions - WINC1501 19.4.4 and latest WINC1501 19.6.1 on two different boards