I know could be totally irrelevant to this post but the new image show if the linux machine is booted with a bright white led
Linux side ready visual notification: when linux boot completes, the usb led lights up (it's bright white)
http://forum.arduino.cc/index.php?PHPSESSID=0kiej3fr5genejinpfjbd3mh14&topic=235360.0
so with the new image white led == bridge is up