My device rebooted (not always):

- changing apn;
- updating weather forecast;
- writing an sms
- opening the application menu;
- opening the terminal;
etc. etc.

Since yesterday it rebooted at least 10 times....

I don't think these are advanced user's tasks.

It's difficoult to reproduce the problem, because the device stays up for 4 hours with no reboot but sometimes reboots 3 times in 10 minutes.

Every reboot is in a different situation.