while (!Serial) ; Weirdness

Hardware Arduino Yún
1

My Yun is acting bizarre with this sketch:

void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
//delay(1000);
while (!Serial) ;
Serial.println("hello");
}

void loop() {
  // put your main code here, to run repeatedly:

}

If I upload this sketch via USB and open the serial monitor I get no output most of the time, occasionally it will work perhaps one out of 10 uploads

If I press the 32U4 reset it works as expected, if I upload via WiFi and then switch the port to USB it works as expected, if I uncomment the delay statement it works as expected.

WTF?????

Details
Host - Ubuntu 13.04 64 bit
Arduino Version - 1.5.5 or 1.5.4

2

It's a long standing bug when using the combo RXTX (native serial access library of the Arduino IDE) and the 32u4. Can you give a try to the latest nightly and try again? We replaced RXTX with JSSC to solve a couple of issues and it should solve this issue as well

3

That took care of it.

I am surprised I hadn't noticed this before, even more surprised I haven't learned to get the nightly build when something weird crops up.

Thanks!!