Before I installed iOS 4.01 on my iPhone 4, I took screenshots in the persistent trouble spots in my house: the kitchen, living room and kids’ playroom. Below are those images, showing 1 and 2 bars respectively.
After installing the update, I stood in the exact same spots and again took screenshots. The iPhone reports the same number of bars, but now they’re noticeably taller.
Next, I stood in the kitchen and placed a call. Despite having 1 bar, I talked for 15 minutes without interruption (holding the phone in my right hand). Finally, I applied the so-called death grip and could not make the bars budge. It was only while in my concrete-walled basement that 1 bar would drop to “No signal.” Other than that, the iPhone flat-out refused to give up that last bar. Impressive.
Finally, here’s a video of myself completing and maintaining a call to my landline that started with two bars then dropped to one with the iPhone in a full death grip. The iPhone never gave up that last bar. Previously, this call would have dropped in seconds. I’m now very curious to hear Steve explain what type of spell iOS 4.01 has cast on my iPhone.
Update: AnandTech has published a thorough look at what’s new.