I just start my phone by updating the latest firmware. It goes nicely and ok until the one (firmware) before the lollipop update. Seems like the file is too big for me to update it through the phone. So, I connect my phone to the PC Companion and update it by itself. Suddenly, when it was updating (after the phone shutdown itself), my USB cable was not detectable by the PC anymore. It just update half of the firmware (not complete). I am not sure what is the actual problem but I think it was the firmware. Now, I just can PowerOff+VolumeUp and it's vibrate once in the 10 seconds and thrice after that. My PCC no more detect my phone. Sorry my bad English. Hope to reply as soon as possible.