Apple said that it was "stunned" to find that its iPhones have for years been using a "totally wrong" formula to determine how many bars of signal strength they are getting.
The company said that’s the reason consumers have been complaining of sudden signal loss when holding the phone in a way the covers a small black strip on one edge of the phone.
A statement released by Apple says, “Upon investigation, we were stunned to find that the formula we use to calculate how many bars of signal strength to display is totally wrong. Our formula, in many instances, mistakenly displays two more bars than it should for a given signal strength. For example, we sometimes display four bars when we should be displaying as few as two bars,” the company said.
“Users observing a drop of several bars when they grip their iPhone in a certain way are most likely in an area with very weak signal strength, but they don't know it because we are erroneously displaying four or five bars. Their big drop in bars is because their high bars were never real in the first place.”
To address the issue, Apple will be issuing a software update "within a few weeks" that will adjust how signal strength bars are calculated and displayed.
The change will adopt a recently recommended formula from AT&T that will more accurately display actual signal strength at any given time. The update will also increase the size of the smaller bars to make them easier to see.
The update will also be available for the iPhone 3GS and 3G, which are also affected by the miscalculated signal strength indicators.
“We have gone back to our labs and retested everything, and the results are the same. The iPhone 4's wireless performance is the best we have ever shipped. For the vast majority of users who have not been troubled by this issue, this software update will only make your bars more accurate. For those who have had concerns, we apologize for any anxiety we may have caused,” the statement said.