I'm trying to use Arduino Uno as ISP to program Arduino Mega 2560 using this Pin connections (Uno->Mega):

slave reset: 10: -> RESET on target

MOSI: 11: -> 51

MISO: 12: -> 50

SCK: 13: -> 52

It runs perfectly when I "Burn Bootloader" from Arduino IDE and LED starts blinking on target. So I assume my pin connections are correct.

However, when I open the Blink example and perform "Upload Using Programmer" in Sketch tab after choosing "Arduino as ISP" in Tools>Programmer it uploads the code but LED on Mega doesn't blink.

I'm afraid that I have problem in my Mega Bootloader hex file and think it's not configuring Pin 13 as a LED pin. But in this case I shouldn't have seen the led blinking after burning the bootloader.

What am I missing here? I appreciate your help. -Bex

  • The problem may be related to reset. See arduino.stackexchange.com/a/19131/3879
    – Milliways
    Jan 4, 2016 at 11:13
  • No, I checked the connections and they look fine. I set the RESET pin as D13 in Arduino Uno and don't think it's wrong. Also defined the RESET pin as D13 in the ArduinoISP Example.
    – baqx0r
    Jan 4, 2016 at 18:03
  • 1
    When you "upload using programmer" the target board's bootloader is not involved, and I believe it actually gets removed by doing that. Apr 14, 2016 at 14:07

1 Answer 1


Find the file called "boards.txt" located in your Arduino installation directory. In my case, the path is "arduino-1.6.5/hardware/arduino/avr/boards.txt". Open it with your favourite text editor and locate the ATMEGA2560 section. (not in notepad, it breaks the file format, notepad++ my choice)

in boards.txt

  • back-up the file incase you break it,
  • find the line : mega.menu.cpu.atmega2560.bootloader.high_fuses=0xD8
  • and change it with : mega.menu.cpu.atmega2560.bootloader.high_fuses=0xD9

Source : http://soc.ninja/documentation/programming-atmega2560-with-arduino-uno-or-mega/#rating-74

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