my iPhone 6 starts to turn on then goes to a blue screen then it turns off again
screen turns on and then goes blue. then it turns off and just keeps cycling
iPhone 6, iOS 8.2
Try to reset your device. This won't delete your data stored on the phone.
- Press and hold the Sleep/Wake button
- Press and hold on the Home button
- Keep holding both buttons until the display turns off and back on with Apple logo on it.
Alternatively, you may go to Settings - General - Reset - Reset All Settings
https://support.apple.com/en-us/HT201559
Hope this helps!