Leonardo uploads and runs, but no Serial (USB) output

I’ve read the troubleshooting guide, and searched for similar issues. Nothing quite matches my issue.

I can upload and run sketches, and my Leonardo USB enumerates to a COM port that I can connect to, but I can’t get any serial output from that Leonardo COM port.

  • Blink uploads and runs fine.
  • (Hardware) Serial1 (pins 0 and 1) works fine to my FTDI cable (shows up as COM4 on my system).
  • Leonardo enumerates to COM6 when plugged in or reset.
  • The Leonardo has nothing plugged into it except the USB cable and ISP programmer.
  • The programmer is genuine Atmel JTAGICE3 and it’s clearly working (Blink uploads and runs).
  • I use Atmel Studio 6 for development (clearly working with this board and my other Arduino variants).
  • Unplugging the programmer and resetting the Leo doesn’t help.
  • Device Manager (Windows 7 64) indicates the Leonardo com port/driver is working fine.
  • I got the Leonardo driver from the Arduino 1.0.1 distribution.
  • I can see and connect to either of the above listed COM ports in my terminal software (Brays Terminal v1.9b).
  • Terminal shows expected output from COM4 (FTDI / Serial1), but nothing when connected to COM6.
  • I figured out that the loopback test can’t work on the Leonardo variant, but I don’t see that documented anywhere.
  • The Arduino itself is an Olimex Olimexino32u4 (Leonardo clone).

What am I overlooking?

Here’s my test code:

#include <Arduino.h>

int led = 9;

void setup() {
	pinMode(led, OUTPUT);
	Serial.begin(9600); //speed is apparently irrelevant
	Serial1.begin(9600);
}

void loop() {
	digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
	delay(1000);               // wait for a second
	digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
	delay(1000);               // wait for a second
	Serial.println("test");      //doesn't work (Leonardo USB)
	Serial1.println("test2");   //works great (pin 0, 1)
}

I'm drowning here, guys. Should I have posted this somewhere else?