We got an Arduino UNO R3 with an atmega16u2 and we can't put it in DFU Mode, we tried using the RESET and the GND but nothing happened. Then we tried using the 5 and 6 pin of the SPI, and it nothing happened again.
Any help would be appreciated, we really need this!
I give you some pics of the arduino, so you can see it...
You can use the working Arduino as a programmer and try to reprogram the USB to Serial device on the non-working one.
You can follow this tutorial for using the ArduionISP sketch:
The firmware you want to load on the 16u2 is located in your Arduino software package: arduino\hardware\arduino\firmwares\atmegaxxu2\Arduino-COMBINED-dfu-usbserial-atmega16u2-Uno-Rev3.hex
You will need to connect the ArduinoISP to the six pin header located in the upper left hand corner, near the AREF label.
Resolved this problem using the parallel port of my computer, the avrdude tool that comes in "Arduino\hardware\tools\avr\bin" within the Arduino software folder.
So restored the Firmaware 16u2 chip with command "avrdude -p m16u2 -c dapa -vvv -U flash:w:firm.hex". firm.hex where is the file that contains the firmware chip.
how did you wire up the Arduino to the computer to get this to work? I seem to be having a similar issue, my UNO is bricked and I'm wondering if re-flashing the 16u2 will solve the issue but I don't have another Arduino as well.
