Hi @studiogamma. Due to a bug in Arduino IDE, the Arduino IDE Serial Monitor or Serial Plotter interfere with the firmware update process, so the cause of the failure you encountered might be that you had Serial Monitor or Serial Plotter open in Arduino IDE while you attempted the update.
Please try this:
Unplug the USB cable of the UNO R4 WiFi board from your computer.
Connect the UNO R4 WiFi board to your computer with the USB cable. ⓘ The reason for unplugging and then re-plugging the cable is that the UNO R4 WiFi is put into a special firmware update mode by the IDE's firmware updater. After using the firmware updater, the board must be power cycled in order to switch it back to the normal mode. So this is done just in case the board was still in the firmware update mode from the previous attempt.
If you have the Arduino IDE Serial Monitor or Serial Plotter running, close them. ⓘ You can close Serial Monitor by clicking the X icon that appears on its tab when selected:
Select Tools > Firmware Updater from the Arduino IDE menus.
The "Firmware Updater" dialog will open.
Select the UNO R4 WiFi from the "Select Board" menu in the "Firmware Updater" dialog.
Click the "CHECK UPDATES" button.
An "INSTALL" button will be added to the dialog.
Click the "INSTALL" button.
An "Installing firmware" process will start, as indicated by the message near the bottom of the dialog.
Wait for the firmware update process to finish successfully, as indicated by the message in the dialog:
Firmware successfully installed.
Click the X icon in the dialog.
The dialog will close.
Disconnect the USB cable of the UNO R4 WiFi board from your computer. This step is essential in order to restore the board back to the normal operational mode after the firmware updater puts it into the special firmware update mode.
Connect the UNO R4 WiFi board to your computer with the USB cable again.
I tried this. I click Install firmware and it runs for about a minute, then makes the 'bing' sound (hardware being disconnected sound) and it says, 'Installation Failed'.
Then it can't see the board, until I unplug and replug it in. During the process it seems to lose the board.
This is for firmware version 0.4.1 on Windows 10 machine.