Hi there!

My cousin unlock my 3g iphone last month but after we did it, most of the time my phone will just hang and I need to puch the home button and power button at the same time but instead of returning the homepage to original settings, itunes with usb image will appear.

Also, I did the upgrade of Cydia to my Iphone and it made my iphone more worse to use.

I hope somebody can help me restore the phone. Just in case also, since I still have a 1yr warranty for my iPhone can I return it with AT&T so that they can replace it with a new one after I restore the firmware?

please help