Galaxy S4 keeps rebooting I recently updated my galaxy s4, and after this update contacts app keep force close from yesterday night my device keep rebooting constantly. already did Google and tried so many things. 

I have tried a number of steps, 


such as taking battery out 
removing SD Card and Sim Card 


but still it remain same. even device is not going for recovery mode and when i tried to go for Odin mode device is not going in downloading mode and its just restarted.
For me a factory reset helped somewhat, although sometimes it still shuts off (about 3 times a week, better than every hour).