In response to mounting reports that the iPhone 4 offers subpar call reception, Apple Inc. today said that an algorithm used in its new smartphone is flawed and promised to update its iOS 4 operating system in the next few weeks.

Users called the company's inaccurate algorithm explanation "hooey" and worse on Apple's support forum.

Apple blamed the faulty formula for problems users have encountered with the iPhone's signal strength, which has been said to quickly plummet when the phone is held in certain ways.

"We were stunned to find that the formula we use to calculate how many bars of signal strength to display is totally wrong," Apple said in a statement issued Friday morning. "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."

Essentially, Apple said that the bogus indicator misleads iPhone 4 users into thinking they have a stronger signal than they really do, and then when they hold their phones in certain ways, the signal diminishes quickly and unexpectedly.

"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," the statement continued.

Apple said it would issue a software update that will replace the flawed algorithm in a "few weeks." The defective formula has been part of the iPhone's firmware since the original 2007 iPhone, Apple said, so the fix will also apply to the older iPhone 3G and 3GS.

Complaints about call and data signal-strength problems in the new iPhone 4 surfaced within hours of the smartphone's launch last week. By the next day, Apple was acknowledging that holding the iPhone 4 can diminish the signal but offered only generic advice, telling users to "avoid gripping it in the lower left corner" or "use one of the many available cases."

Apple's explanation today didn't address reports by many users that the iPhone 4 dropped calls when they held it a certain way.

On Apple's support forum, most people were skeptical that the upcoming software fix would really solve the problems they have with their iPhones.

"The announcement is totally bogus," said a user identified as "Lisa4720" on a fast-growing support forum message thread. "Here's the problem with their new claim: 3GS reception in my home and my husband's office was always 4-5 bars. Today [with iPhone 4] it is nil, nada, nothing even after Apple replaced the iPhone 4s, it remained the same. It's all hooey people. Total, unbelievable hooey."

Other iPhone 4 owners backed up Lisa4720's claim that older iPhones, such as the 3G, retain calls in locations where an iPhone 4 drops them, regardless of the signal strength.

A few stood by Apple, however, and speculated that the software update might solve the dropped call problems many have reported. "My guess is the algo[rithm] they use to calculate the bars used may stop the dropped calls as well depending if the number of bars calculated is linked to the connection," theorized a user identified as Andy Thomas. "The logic could be 'if the number of bars = 0 then drop the call.'"

Spencer Webb, an antenna design engineer, has said he believed the reception problem was in the design of the iPhone 4, specifically in Apple's decision to move the cellular and Wi-Fi antennas to the exterior of the case. Webb has recommended that users hold the iPhone 4 in what he called the "Vulcan iPhone pinch" to minimize contact with the external antennas.

Webb was not immediately available to comment on Apple's claim that a software fix would likely address the iPhone 4's reception issues.

In its statement, Apple also apologized to users "for any anxiety we may have caused," but maintained that the iPhone 4's wireless performance is the "best we have ever shipped."

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His e-mail address is gkeizer@ix.netcom.com.