Apple has rolled out iOS 4.0.1 update which “improves the formula to determine how many bars of signal strength to display.”
This update iOS update works for all iDevices running over iOS 4.0. So, grab out the new iOS update, experience its new feature and write in comments either it really improves iPhone 4 signal issues as stated by Apple?
Apple also has updated iOS 3.2.1 for iPad with a number of new fixes as:
Note: The users who have jailbroken or unlocked devices should stay away from these new iOS updates.
Download iOS 4.0.1 for iPhone 4
Download iOS 4.0.1 for iPhone 3GS
Download iOS 4.0.1 for iPhone 3G
Download iOS 3.2.1 for iPad