I have an Anduino Uno R1 and the ATmega8U2 on. It does not respond correctly. How can I use another Arduino Uno R3 in order to reinstall the correct firmware? What I want to avoid it to solder the resistor because I am not very good with the soldering iron.

As fas as I understand there are some pins close to the AREF pin that can be used in order to attach a programmer. Also how can I temporally attach them without the need of a soldering iron? On the R1 the pins are just some exposed metal. How can I connect to them?

Also, if I load into the other Arduino the programmer, then how can I load the firmware using GNU/Linux into the ATmega8U2?

enter image description here

  • Those pads are actually plated through-holes. But the are filled with solder during manufacturing. You can suck the solder out with a solder sucker. Then solder in some headers. It helps to first add some leaded solder to the “pads”. That way the unleaded solder that’s already there will mix with the leaded, and will lower it’s melting point. The other option is to use the DFU method of updating the firmware (which I think you were talking about in you question).
    – Gerben
    Apr 21, 2018 at 9:18
  • Even if I solder the header then how I will load the firmware on GNU/Linux? Apr 21, 2018 at 9:32
  • I think there is a guide on the Arduino website for this. Can’t really check at this moment.
    – Gerben
    Apr 21, 2018 at 9:47
  • it does not respond correctly - in what way? It is extremely unlikely that the Atmega8u2 has become corrupted.
    – Nick Gammon
    Apr 21, 2018 at 9:54
  • You can suck the solder out with a solder sucker. - you can also solder wires to them. However the OP said that he is not very good with a soldering iron.
    – Nick Gammon
    Apr 21, 2018 at 9:55

1 Answer 1


There is an official guide. Arduino as ISP and Arduino Bootloaders

But you need to add the 2x3 ISP pin header since some of the signals isn't available on D0-D13 or any other pins.

  • None of the signals on the '8U2 are available on Female headers except power & Gnd. One must connect to the 2x3 ISP header for the '8U2 that is shown below the chip in the picture.
    – CrossRoads
    Jan 9, 2019 at 17:36

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