Windows
Download AVRDUDESS and once installed and running you’ll want to change the following settings;
- Programmer: Atmel for bootloader using App Note AVR 109/911
- Port: Port created when device is in reset
- Flash: .hex file with the downloaded firmware files
- MCU: ATmega32U4
To identify the Correct COM Port look at the port list with the device in its running mode, then press the reset button on the device and refresh the list.
The new COM port wil be the one you’ll want to use to flash the device.
Now press the reset button before the program button, this will then begin flashing the device on the COM port created by the device.
When the firmware update has finished you'll get the message "avrdude done. Thank you" and the device will reset into its running state.