Iphone 6 stays on logo and flicks over and over
I have installed the latest update and now the phone stays on the apple logo with a progress bar that goes for about 5 secs and then flicks back to the beginning again. I have pressed the home/off buttons etc etc and after sliding to upgrade and entering my code it just goes back to the above. Over and over again. Every now and then it flicks to my home screen for 1/2 a second but then back to the logo. I have had a phone call, but it just rings continuing on with the logo, I can activate siri but again still seeing the logo. Its as if the phone is on, but the screen isn't. HELP!
iPhone 6