Arduino UNO R4 WiFi as bootloader burner

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Hi @itz_g3ermox. Yes, you can use the UNO R4 WiFi or UNO R4 Minima board as a programmer to burn the bootloader to your 3rd party UNO R3 clone/derivative board.

The procedure is slightly different from how it would be when using an UNO R3 or other AVR board as the programmer. I'll provide instructions for doing it:

ⓘ In the instructions below, the board used as an "Arduino as ISP" is referred to as the "programmer board". The board the bootloader is being burned on is referred to as the "target board".

A. Prepare "Arduino as ISP" programmer

  1. Disconnect the USB cables of the Arduino boards from your computer.

  2. Make the following connections between the pins on the "programmer board" and the "target board".

    Programmer Target
    10 reset
    12 SPI CIPO (AKA "MISO")
    5V 5 V
    13 SPI SCK
    11 SPI COPI (AKA "MOSI")
    GND ground

    ⓘ The documentation for the target board will identify the location of these pins. If you are using an official Arduino board, check the pinout diagram on the documentation page for the board.

  3. Connect the "programmer board" to your computer with a USB cable.

  4. Select File > Examples > 11.ArduinoISP > Arduino ISP from the Arduino IDE menus.
    The "ArduinoISP" sketch will open in Arduino IDE.

  5. Add the following line at the top of the "ArduinoISP" sketch:

    #define USE_OLD_STYLE_WIRING

  6. Select your "programmer board" from Arduino IDE's Tools > Board menu.

  7. Select the port of your "programmer board" from Arduino IDE's Tools > Port menu.

  8. Select Sketch > Upload from the Arduino IDE menus.

  9. Wait for the upload to finish.

You are now ready to burn the bootloader using your "Arduino as ISP" programmer.

B. Burn Bootloader

Instructions for burning the bootloader:

ⓘ It is not possible to do this via "Arduino Web Editor". You will need to use Arduino IDE or Arduino CLI.

  1. Select the "target board" from the Tools > Board menu, and any other custom Tools menus (e.g., Tools > Processor).
  2. Select Tools > Programmer > Arduino as ISP (ATmega32U4) from the Arduino IDE menus.
  3. Select Tools > Burn Bootloader from the Arduino IDE menus.
  4. Wait for the process to finish successfully.
  5. Disconnect the USB cable of the "programmer board" from your computer.
  6. Disconnect the "programmer board" from the "target board".