I was able to answer calls on nexus 4 running previous OS versions. After updating to OS 5, the phone only rings without showing a phone sign for me to swipe to the right too answer incoming call. Now the screen is blank and dark and the phone rings. I have to press the power on, enter my password to the nexus 4 and then swipe to the right to answer. Please help so I can answer calls without the hassle. Thank you.