The phone is unlocked using ultrasn0w.
I've tried to restore it multiple times, it always has the same issue.
At first I thought it was the flaw with the antenna but it might be the 3G network or the sim card I am using.
I will try to change it tomorrow to see if it fixes my problems.
I have an Iphone 4G with firmware 4.1.
I've been having issues with the phone since I bought it.
I am aware the phone has some problems with the antenna and that it looses signal quickly when not held the right way.
I bought a very good cover that seems to take care of the problem...