The large signal drops experienced by iPhone 4 users have not been caused by holding it wrongly; apparently the signal was not there originally.
Apple has claimed the issue is with the formula it uses to calculate signal strength and this has been displaying the reception as two bars higher than it should be.
In a letter to iPhone 4 users, published on the company website, Apple 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 4 or 5 bars."
It added: "Their big drop in bars is because their high bars were never real in the first place."
To fix the problem Apple is planning to adopt a new formula recommended by US mobile network AT&T, as well as making the first, second and third bars bigger "so they will be easier to see."
It will release a software update for all versions of the iPhone "within a few weeks" as the letter claimed the formula problem has been present in all of them since the start.
"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 apologise for any anxiety we may have caused," the letter concluded.
"We hope you love the iPhone 4 as much as we do."
