It seems like iOS 4 will be updated to 4.0.1 on Monday, This is according to AppleInsider who has posted that Apple is working on new Firmware update and is going to Release iOS 4.0.1 on next Monday, This is because some bugs that discovered in the iPhone 4.
Here’s the important part from AppleInsider post:
Readers report that Apple’s tech support forums originally confirmed that a iOS 4.0.1 software fix addressing the issue would ship early next week (as early as Monday), before the comments were subsequently taken down along with all the other related discussion about the matter.
The fix is expected to address a issue in iOS 4 related to radio frequency calibration of the baseband. Readers who saw the original forum discussions say that the issue is believed to occur when switching frequencies; because the lag is allegedly not calibrated correctly, it results in the device reporting “no service” rather than switching to the frequency with the best signal to noise ratio.
From the most discoverd issues and problems in the iPhone 4 is losing signal while holding it in your Hand, and Steve Jobs answered an iPhone 4 user telling Home “Hold it in diffrent Way”