default/sanguino/firmwares/README.txt

Arduino Uno and Mega 2560 Firmwares for the ATmega8U2

This directory contains the firmwares used on the ATmega8U2 on the Arduino
Uno and Arduino Mega 2560.  The arduino-usbdfu directory contains the DFU
bootloader on the 8U2; the arduino-usbserial directory contains the actual
usb to serial firmware.  Both should be compiled against LUFA 100807.  The
two .hex files in this directory combine the dfu and serial firmwares into
a single file to burn onto the 8U2.  

To burn (Uno):
avrdude -p at90usb82 -F -P usb -c avrispmkii -U flash:w:UNO-dfu_and_usbserial_combined.hex -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -U efuse:w:0xF4:m -U lock:w:0x0F:m

To burn (Mega 2560):
avrdude -p at90usb82 -F -P usb -c avrispmkii -U flash:w:MEGA-dfu_and_usbserial_combined.hex -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -U efuse:w:0xF4:m -U lock:w:0x0F:m


Note on USB Vendor IDs (VID) and Product IDs (PID): The arduino-usbdfu
project uses Atmel's VID and MCU-specific PIDs to maintain compatibility
with their FLIP software.  The source code to the arduino-usbserial
project includes Atmel's VID and a PID donated by them to LUFA.  This
PID is used in LUFA's USBtoSerial project, which forms the basis for
arduino-usbserial.  According to the LUFA documentation, this VID/PID
combination is:

 "For use in testing of LUFA powered devices during development only,
 by non-commercial entities. All devices must accept collisions on this
 VID/PID range (from other in-development LUFA devices) to be resolved
 by using a unique release number in the Device Descriptor. No devices
 using this VID/PID combination may be released to the general public."

The production version of the arduino-usbserial firmware uses the
Arduino VID.  This is only for use with official Arduino hardware and
should not be used on other products.