Why does my phone keep turning off/restarting?

Question

Mobile devices

The problem is this: I have a Samsung galaxy gio S5660 phone. He is 4 years old. It worked perfectly, I need it as a dialer, there are practically no third-party applications, I decided to flash it, on the version of android 2.3.6, I flashed it, but my battery died in 2 hours. Returned everything back. He worked for 2 months before the onset of winter, now what is happening, he lies quietly in his pocket, you take it out. Received the call, you end it, and the phone is turned off at the same time, all this happens on the street, at home it seems without problems. Then for 30 seconds you need to hold the button on. then it starts. It also happens to start, and then reboot itself, then again on. Please let me know what can be done about this. The new one is not yet an option)) Thank you.

Answer 1

All warranties and service life have expired. To the morgue.

Answer 2

Has the battery been changed recently?
But most likely the board itself has already become unusable, it will be problematic to solder it at home - you need to be "left-handed", so it's better to change the handset and that's it.