The problem, BusinessWeek reported Thursday, may be faulty firmware in a communications chip supplied by Munich-based Infineon. BusinessWeek said its confidential sources backed a report released earlier this week by Nomura Securities analyst Richard Windsor that pointed to the firmware.

Patch May Be Imminent

An Infineon spokesperson declined to address the iPhone issue directly, but defended Infineon's technology, saying it works fine in other 3G phones. "Our 3G chips are, for example, used in Samsung handsets and we are not aware of such problems there," he said.

Apple is reportedly working on a firmware upgrade to fix the problem. USA Today reported that the fix could be available via iTunes as early as next week, but Apple has not commented.

Tim Bajarin, principal analyst with Creative Strategies, said in an e-mail, "Historically, Apple does not respond to something like this automatically just because there are reports of problems. If there is merit to the issue, they work overtime to fix it and usually, at the point of the fix, that is when they respond."

Bajarin expects Apple to eventually make things right with its 3G customers. "Apple prides itself on its customer -service reputation and I would be surprised if they don't go the extra mile to make sure anything that impacts that image will be corrected as fast as possible," he said.

Problem Is Global

Another theory is that Apple programmed the Infineon chip to require a stronger-than-needed 3G signal, so some users are being knocked down to slower networks even though there really is sufficient 3G bandwidth.

Alternatively, it may be that AT&T hasn't built out its 3G network adequately to handle the traffic. That, apparently, is what Apple Store employees have been telling upset customers.

But technology analyst firm Nielsen IAG says the problem is global. "Apple has had the same problem in every market where the (3G) iPhone is sold," Roger Entner, a senior vice president at the firm, told USA Today. "It's probably the device."