On the Yun the well-known on board LED at pin 13 is now red no more orange as on the Uno and other boards. So be not confused red blinking is green light on the Yun after uploading the standard test sketch! 
On the Yun the well-known on board LED at pin 13 is now red no more orange as on the Uno and other boards. So be not confused red blinking is green light on the Yun after uploading the standard test sketch!