I can only flash my Uno via ICSP, not USB/Serial (ttyACM0)

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1

I may have fried something on my Uno.
I have 2 Unos. One, I can flash just fine from arduino.
The other one, also shows up as ttyACM0, but flashing gives me the stk500 not responding error.

If I use the ICSP header, I can reflash the Uno and then it works fine.
I tried to reflash the 16U2 (my Uno r3 is the one that won't flash via USB/Serial), the procedure with dfu works fine, ttyACM0 goes away, then comes back, everything looks good.
And then I plug it back into the arduino IDE, and it won't flash. If I plug my other Uno without changing anything, again that one flashes fine.

What are possible failure scenario there?

2

Are you saying you've programmed the '328p on your Uno r3 via ICSP? (ie, by doing 'upload using programmer')

If you do that, it erases the serial bootloader; you need to connect it to the ICSP programmer and do 'burn bootloader' if you want to again upload sketches via serial again.

3

I may have fried something on my Uno.
I have 2 Unos. One, I can flash just fine from arduino.
The other one, also shows up as ttyACM0, but flashing gives me the stk500 not responding error.

If I use the ICSP header, I can reflash the Uno and then it works fine.
I tried to reflash the 16U2 (my Uno r3 is the one that won't flash via USB/Serial), the procedure with dfu works fine, ttyACM0 goes away, then comes back, everything looks good.
And then I plug it back into the arduino IDE, and it won't flash via USB, but it'll flash via ICSP. If I plug my other Uno without changing anything, again that one flashes fine via USB.

What are possible failure scenario there?

4

DON'T CROSS POST!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
http://forum.arduino.cc/index.php?topic=467864
Reported

5

Threads merged.

6

DrAzzy:
Are you saying you've programmed the '328p on your Uno r3 via ICSP? (ie, by doing 'upload using programmer')

If you do that, it erases the serial bootloader; you need to connect it to the ICSP programmer and do 'burn bootloader' if you want to again upload sketches via serial again.

Aaah, that would explain why I had the problem then, I didn't realize uploading via ICSP also deleted the bootloader.
I re-burned a bootloader, and things are ok again.

And sorry about the crosspost, I couldn't figure out which of those 2 places was best for this message.

Thanks for your help.