My phone is in bootloop and i can't access the fastboot, if i turn off the phone and just enter the usb cable is turning on and showing me the android robot exactly like in fastboot but the windows don't recognize it (Unknown Device). If i press power button + Volume Down and then enter the usb cable is not doing anything. What can i do? Ps. I have the good drivers intalled. Is doing this after i wanted to change the rom. Sorry for my bad english.