I had some issues with Firmware Updater. I add my findings here.
I received my first Arduino UNO R4 WiFi about a month ago. I don't know which firmware it had.
I purposely waited with updating its firmware (and using WiFi with this board) until a stable method became available. That is why I then created this topic to be sure.
I had an issue with the Firmware Updater on my first board, see
Arduino UNO R4 WIFI firmware updater - UNO R4 / UNO R4 WiFi - Arduino Forum
It consistently failed to install 0.3.0.
I then installed 0.2.1, success on the first attempt.
Then I tried to install 0.3.0 again, success at first attempt.
Now I received my second Arduino UNO R4 WiFi.
Its firmware came as 0.2.1, checked with method in post #8.
I tried to install firmware 0.3.0 with Firmware Updater, result installation failed.
I didn't observe the installation behavior, and didn't check the firmware version.
I then tried to install firmware 0.2.1 with Firmware Updater, result installation failed.
But the installation behavior looked ok, until some idle time at the end.
I then tried to install firmware 0.3.0 with Firmware Updater, result installation failed.
But the installation behavior again looked ok, until some idle time at the end.
Check of the firmware showed 0.3.0
Cycling between 0.2.1 and 0.3.0 always showed the same behavior.
Of course I had to disconnect / reconnect USB after every update.
Conclusion: for me the Firmware Updater method works, but seems to have some quirks.
-jz-