Why does it keep shutting down?

I have a 3.52 m33 - 4 psp and i just unbricked it using universal unbricker. Problem is that when i ever i play a game for more then 20 min it shuts down on me. I charged it to the maximum and everything. Sometimes it restarts too and its getting worse. Now it restarts like every 5 min. Itried it with out the battery and with the charger but the same problem occurs. Is there anything i can do to make it stop shutting down and restarting?

 

go back to 1.50, and then upgrade to 3.52 m33-4. something might have gone wrong in the flashing.