I purchased an 16GB iPhone last week, unlocked successfully by ZiPhone 2.4. My iPhone worked perfectly for two days then it started shutting down when it is in sleep mode for more than 15 seconds. The only way to turn iPhone on is to press both Home and ON/OFF buttons. The iPhone is OK when it is plugged in (charging) or connected to a PC.
I've tried everything from a complete reset to a complete restore as a new iPhone from iTunes but the problem persists.
I would like to hear from anyone who has the same problem or know how to fix it.
Thanks in advance