Hi! My Arduino Uno R3, which I'm trying to use the USB keyboard FW for, won't let me flash it. I've done this before on an older version with 8u2, but AFAIK it's the same procedure.
dfu-programmer atmega16u2 erase dfu-programmer: no device present.
I don't understand why. It just resets when I short the two pins you're supposed to short. It doesn't disconnect, my Mac still shows dev/TTY and dev/CU under serial ports (in addition to bluetooth etc.). It just won't go into DFU... FW is 0.01.