Quit a few people have reported issues with the iPhone 4′s signal when held certain ways, a phenomenon that has even been displayed on video. While people are quick to bash Apple over this, they have often failed to realize that many other mobile phones including the Google Nexus One have similar issues. Of course, the problem was only compounded when Apple CEO Steve Jobs informed one person that they were simply holding the phone wrong.

Now, it is looking less like the issue is hardware related and more of an issue with iOS 4. According to AppleInsider, an iPhone 4 showed less signal than an iPhone 3GS, even though the iPhone 4 was able to achieve a similar or in some cases better call quality.

Further testing is said to show devices running iOS 4 can easily reproduce the signal drop when connected to a WWAN 3G network, but are not present when connected to a 3G Macrocell. If it was a hardware issue, the problem should be reproducible regardless of the type of network it is connected to.

An update to iOS 4 is said to address an issue with the radio frequency calibration in the baseband. Expect to see iOS 4.0.1 hit iTunes as early as Monday. [AppleInsider]