I just bought a raw Atmega328p microcontroller. I am attempting to flash it with the Arduino bootloader.

The process seemed relatively straightforward as I had just followed the posted tutorial (https://www.arduino.cc/en/Tutorial/ArduinoISP).

Everything seemed to go fine and I even got a message after the second attempt with a message of 'Burning Bootloader Done'. I am targeting the device as if it were an Arduino Pro Mini.

I then moved onto program the chip with an Arduino sketch via the FTDI programmer. However, the sketch upload fails. It says that it is out of sync. I verify that everything is wired up correctly, yet it still fails. I then remove power to the Atmega328p chip (just to see if I get a different error) yet I still get the out of sync error.

This has me questioning whether or not the bootloader was even flashed in the first place. So how do I know if the bootloader actually was successful? A couple things to note:

  • When I power on the Atmega328p, the PB6 output starts blinking immediately. I would assume that if there were a bootloader, there would be a moment of pause until the regular program starts. Should I expect to see a pause if the bootloader is on the chip?

  • If the bootloader is on the chip, should I even expect to see the Atemga328ps default heartbeat?

  • When I flash the chip with the bootloader, it says that it could take up to a minute to finish. However, it only takes 6 seconds until it states 'Bootloader Finished Burning'. This seems like it's happening too fast.

If we determine that the problem is due to something else (i.e. not the bootloader), I will begin a new discussion. However, right now I'm just curious how I know if the bootloader is actually on the device.

  • 1
    The LED blinks while the bootloader is running. That is the only "heartbeat" there is. If it blinks forever then there is no sketch installed.
    – Majenko
    Commented Aug 23, 2016 at 20:48

1 Answer 1


See my page about burning bootloaders.

The sketch there has a "verify" option so you can check if the bootloader was burned.

See my post What happens when code is uploaded using the bootloader?.

With Optiboot installed you expect to see three flashes:

Optiboot start

As for your other problems, see Have I bricked my Arduino Uno? Problems with uploading to board.

You may well not have set the fuses correctly.

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