Flash Atmega32u4

1. Open atmegaduck/atmega_duck.ino with the Arduino IDE.
2. Under Tools > Board in the WiFi Duck AVR section, select your board; for example, Sparkfun Pro Micro.
3. Connect the Atmega32u4 board via USB and select its port under Tools > Port.
4. [Optional] Under Tools you can enable the LED and set its pin. You can also change the USB ID to make it appear as a certain type of keyboard.
5. Press Upload.

Unbrick Atmega32u4

If you flashed your Atmega32u4 board with the wrong bootloader, it will no longer appear in the port selection after you connect it.
To solve this, you need to:

1. Connect the reset pin RST to ground GND. Preferably with a jumper wires, because you need to be able to disconnect it quickly.
2. Open a sketch, atmegaduck/atmega_duck.ino or an empty sketch.
   Make sure to have the correct board selected under Tools > Board!
3. Connect the board with the wire still connected.
4. Press Upload and as soon as you see Compiling... turn to Uploading..., disconnect the wire.

Now it should flash the sketch and the correct bootloader.