
When your finger or hand touches a spot on the phone's lower left side , the signal can significantly degrade enough to cause you to lose your connection. AlthoughiPhone 4 scored high on other testing grounds such as battery life, sharp display and high-quality video camera.
The Signal issue only happens when you hold the phone a certain way and if you put a case on it, you won't have any problems. This is an hardware issues so Apple can't fix them, till they come out with the next generation iPhone.

The second minor issue is of yellow spots,(Shown in a red circle) is a temporary issue which i think would fade away when you use it.Fix:- just get any pair of gloves, latex, cotton/acrolyic/wool and keep in handy with you. When you need to make a call ,put them on, the phone will work with no dropped calls.
OR
Get your FREE iPhone4 Case now.
