sudo apt-get install gcc-avr binutils-avr gdb-avr avr-libc avrdude
git clone https://github.com/ultimachine/Drude-Firmware.git
cd Drude-Firmware
git submodule init
git submodule update
make
enter DFU Mode by holding button S2 and momentarily press button S1
Verify DFU Mode:
Run: lsusb | grep 2ff4
Output: Bus 003 Device 008: ID 03eb:2ff4 Atmel Corp.
Run:
dfu-programmer atmega32u4 erase
dfu-programmer atmega32u4 flash VirtualSerialDigitizer.hex
dfu-programmer atmega32u4 reset