Test Board Arduino Leonardo Arduino Leonardo pinout Bootloader BootloaderCDC.hex $ avrdude -p atmega32u4 -c usbasp -U flash:w:BootloaderCDC.hex Prerequisite AVR-Common Compile and build $ cd ~/work/avr $ git clone https://github.com/hokim72/ATmega32U4.git $ mkdir ATmega32U4/project_dir/build; cd ATmega32U4/project_dir/build $ cmake-avr .. $ make flash