I have received my Mega2560 but cannot upload a sketch. The Arduino GUI does not let me select the serial port, it is greyed out.
I have arduino version 21 installed on a Debian squeeze system. The arduino shows up as /dev/ttyACM0.
This is what I have atready done:
in ~./.arduino/preferences.txt serial.port=/dev/ttyACM0
checked permissions: my user is in the dialout group which has r/w permissions on the device. echo "something" > /dev/ttyACM0 lets the RX led on the board blink.
Still no luck with the GUI.