Hi @mesko0. I suspect the problem is that you have the wrong board selected from the Arduino IDE's Tools > Board menu. When you are burning the bootloader, you must select the target board from that menu, so in this case, you should select Tools > Board > Arduino AVR Boards > Arduino Uno. Only the programmers that are relevant to programming the selected board are shown in the Arduino IDE's Tools > Programmer menu and the "Arduino as ISP" programmer is not relevant for programming the Nano Every, which uses UPDI programming rather than ISP.
The full procedure:
- Make the following connections between the Arduino board you will be using as the programmer and the target. Refer to the "Connections" table on the SPI library reference page to determine the pins:
Programmer Target MISO MISO VCC 5V (VCC on 3.3 V boards) SCK SCK MOSI MOSI 10 RESET GND GND - Connect the programmer board to your computer with a USB cable.
- Select File > Examples > 11.ArduinoISP > Arduino ISP from the Arduino IDE's menus.
- Select your programmer board from the Arduino IDE's Tools > Board menu.
- Select the port of your programmer board from the Arduino IDE's Tools > Port menu.
- Select Sketch > Upload from the Arduino IDE's menus.
- Wait for the upload to finish.
You are now ready to burn the bootloader using your "Arduino as ISP" programmer.
Instructions for burning the bootloader:
- Connect an ISP programmer to the ICSP header on your Arduino board.
- Select the target board from the Tools > Board menu and any other custom Tools menus (e.g., Tools > Processor).
- Select the appropriate programmer from the Tools > Programmer menu.
- Tools > Burn Bootloader
- Wait for the process to finish successfully.
I will warn you that I have not had luck using the Nano Every as an Arduino as ISP programmer when I tried it some time ago (details), but it had nothing to do with the problem you are having now and it's certainly worth a try.