When my phone is asleep, ie, screen is blank, pressing the home button once should bring up the unlock screen. My phone is under a month old and only sometimes does this happen. The other times a single press of the home button results in a pause before siri opens so I then have to touch the screen in order to clear siri so I can unlock my phone. Also, I have the known problem with the volume going mute if I try to adjust the ring volume using the side buttons. Have I got a duff handset?!