I recently updated my S4 to 4.4.2 (I've unknowingly had auto update switched off).
Since then it has been spontaneously restarting.
No particular pattern to how often it happens although it never happens in flight mode.
There are quite a few reports of this problem with 4.4.2 but no-one seems to have really pinned down the issues as far as I can tell.
I've tried some simple fixes that have worked for others.
- Turned off auto switching between WiFi and mobile data
- Removed micro sd card
- Removed battery for an hour, then replaced it.
- Shut down, removed SIM, power up, shut down, replace SIM, power up
None of this seems to have worked.
I'm not keen to try rooting the phone, as I'm not sure I could do it and it's a work phone so I don't want to brick it
If anyone has other suggestions I'd be keen to hear them.