Apple's iPhone 4 launch last month has been touted as the single most successful launch in the company's history, with That, however, doesn't explain the related performance problems like dropped calls some users have encountered and how they seem to disappear when using a bumper case or by simply avoid touching the dead spot on its left bottom corner. It looks like we'll have to wait "a few weeks" to see if the update does anything more than just make the signal bars more accurate. Apple also said that customers can return undamaged iPhones within 30 days of purchase for a full refund.