Restore 8U2 bootloader on Arduino Megga board

[Alan Marconett]

Has anyone restored (re-flashed) the Atmel 8U2 on the Arduino Mega2560 board?

 

Alan  KM6VV

[Austin Hendrix]

I haven't needed to flash the 8u2 on my Mega2560 board, but it should be
possible if you have an ISP.

Be careful with your terminology; "bootloader" usually refers to the
software on the Atmega2560 that allows loading firmware over the serial
line, while the 8u2 is the USB to serial conversion chip. Which one are
you talking about?

-Austin

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[Alan Marconett]

Yeah, I'm getting confused myself! I have an STK500, and I can program the
bootloader/program space on the 2560. In addition to the clearly marked ISP
header for the 2560, there is also an ISP header for the 8U2 (don't ask)
which is how I got into trouble! My 8U2 no longer looks like a USB, and I
haven't been successful trying to run flip (flip's a flop). My STK500 and
Atmel Studio 4 apparently can't program the 8U2. I loaded Atmel Studio 6.0
onto another computer, and while it does recognize the 8U2, it wants a USB
STK500 as far as I can tell (haven't tried to learn all of it). Flip does
not like the "combined" 8U2 hex (looks more like html) file I've found on:

https://github.com/arduino/Arduino/tree/master/hardware/arduino/firmwares

And since the code on the 8U2 is bricked, I doubt if flip could load it
anyway.

My sad story.

Alan KM6VV


>On Behalf Of Austin Hendrix

[Austin Hendrix]

I would try to use avrdude to load the firmware with your ISP
programmer, as suggested on the firmware page you linked.

You may have to change the programmer option; try -c stk500 instead of
-c avrispmkii

-Austin

[Alan Marconett]

I can look up avrdude and try that. I thought it was hardware?

I did find under tools in Atmel Studio 6 a "load STK500" option, so that
might get there.

Still not clear on the hex file, I did drill a little deeper on the
downloads and found a hex file.

Thanks!

Alan