I tried letting the Arduino IOT CLOUD interface do the update. It finds the board OK but when it tries to prepare it, it looks like the board just disappears "We could no longer find the device...".
I tried doing the firmware upgrade from Arduino IDE using Tools/WiFi101/WifiNINA firmware updater but when I select "Open Updater sketch" nothing happens.
Also, I don't see a "Check Firmware Version" example sketch for this board anywhere in Arduino 1.8.13 or 1.8.15 and teh Examples for MKR1000 on Examples menu does not seem to include any WiFi examples.
Am I missing something?