1 more problem I got is this.
After a call or wake up from long sleep, the signal's status will change to gray colour ( it was blue for normal ), and i cannot make any call / surf the web, turning airplane mode wont help, it wont turn to airplane mode, all I can do is restart the phone.
If I leave it as it is, it prompted : process.phone.android has stopped working, waiting wont help, force close it will make the phone unusable to phone calls ( signal will get a red "x" ).
Happen 3 times today when I'm outside. Restarted the phone 3 to 4 times, each restarts consume 2% of battery.
I don't encounter this problem very often, just sometimes.