The new Firmware is up https://www.bitmaintech.com/support.htm?pid=007201407180243004432lBQW28O0633
Quote "No beeper altert when there is no immediate hashing work. During the normal mining, Green LED is always on. If there is no immediate hashing work for 1 second, the Green LED will turn off. If it lasts more than 1 minute without hashing work, green LED is kept off and beeper rings"