arduino/Arduino — pull request #1267 by cmaglie (2013-02-05 20:08:54+00:00)
Title: Bugfix for garbage data coming from serial port after reset. (Arduino Due)

After reset garbage may show up from Serial port due to a firmware bug on the atmega16u2.

Here the relevant forum topic:
http://arduino.cc/forum/index.php/topic,134847

Here the updated .hex for the 16u2:
https://github.com/arduino/Arduino/blob/976f7588b7f68bd3c5fce52c15ccfe738589085a/hardware/arduino/sam/firmwares/atmega16u2/Arduino-DUE-usbserial-prod-firmware-2013-02-05.hex

Please check if the updated firmware fix the issues and report back here.
Thanks.
C