I have this issue for about 2 months, I have tried many workarounds and I still don't see any pattern in behaviour of shut downs nor workaround.
Symptoms:
- iPhone 5 (A1429) worked flawlessly with iOS 6 for about 1 year. With iOS 7.0 it was still good, I have not experiemced any problems.
- Random shut off started with iOS 7.0.2 (I have skipped iOS 7.0.1)
- iPhone shuts off randomly about four times per day. I get black screen, no backlight, no response form power or home button. Sometimes isn't even possible to restart it (holding Power+Home). I need to repeat process until I get lucky.
- When I put iPhone to sleep (power button), I have only 70% that it wakes up again. When I prevent it from sleep, it doen't shuts off.
- I have experienced issues with wifi (all time not related to IOS version). I need strong signal to wifi working properly. Maybe there are some issues with series of chip somehow related to this.
What does not helped:
- iOS 7.0.5
- iOS 7.1 beta 4
- iOS 7.1 beta 5
- Reset device to factory settings (clean update through DFU mode). Even with complete clean system with factory settings and iCloud turned off I experienced shut-offs.
- Turning off iCloud, app background sync, reduce motion...
- Reset network settings
- Restore from iTunes backup
- Charging battery. Problem occurs in any charge state even during recharging.
No need to say how frustrated I am. I need to carry two phones and tell everyone, that my iPhone doesn't sometimes work...