Can't reset Yùn in Failsafe Mode

The ethernet connection is not working, the "unknown device" appears and disappears rapidly from the connections menu, and if i type in my browser http://192.168.240.1 or http://arduino.local it can't find the page.

Now the wan led (yellow) is blinking, sometimes the wlan led (blue) blinks for a while and the usb led (white) goes high every 5/6 minutes for 1/2 seconds.