Re-flash the ATMEGA8U2

The ATmega8U2 firmware source code is available . The ATmega8U2 is loaded with a DFU bootloader, which can be activated by connecting the solder jumper on the back of the board (near the map of Italy) and then resetting the 8U2. You can then use Atmel's FLIP software (Windows) or the DFU programmer (Mac OS X and Linux) to load a new firmware. Or you can use the ISP header with an external programmer (overwriting the DFU bootloader). See this user-contributed tutorial for more information.

The "See this user-contributed tutorial for more information" link doesn't work. Where can I find this tutorial?

If you've got Windows, here are a couple of useful links:

http://arduino.cc/en/Hacking/DFUProgramming8U2 http://andrewmemory.wordpress.com/2011/04/14/upgrading-the-arduino-uno-8u2-using-flip/

Hey,

I couldn't find many good resources on reprogramming the 8U2, so after attempting it successfully, I blogged about it. You can find it here:

http://blog.ethanfrei.com/2011/10/arduino-uno-revived.html

Hopefully that will help you out!