It has only been officially available for a day, but already the iPhone is attracting complaints from users who are less than impressed with the phone's reception - and the company's response to the problem.
Reports claim that signal strength diminishes when users cover the bottom left corner of the phone with their palm. The problem appears to stem from the position of the phone's antenna, a stainless steel band around the edge of the device.
Apple has told users to hold the device differently, or buy one of the "bumpers" it sells for the device, a case that covers the edges of the phone.
"Gripping any mobile phone will result in some attenuation of its antenna performance, with certain places being worse than others depending on the placement of the antennas," Apple said in a statement.
"If you ever experience this on your iPhone 4, avoid gripping it in the lower left corner in a way that covers both sides of the black strip in the metal band, or simply use one of many available cases."
An email exchange purportedly between a customer and Apple chief executive Steve Jobs published on tech blog Engadget was more succint. When the problem was outlined, the response was: "Just avoid holding in that way."
Customers have posted videos online demonstrating the problems with the antenna. The phone signal drops out when users cover the bottom left-corner of the device with their palm to make a call, according to the videos.
"That is exactly what is happening to me," said Jennifer Sue (21), a student at the University of Southern California who waited overnight to buy the phone in California. "Everything else is running smoothly."
Mr Jobs unveiled the iPhone 4 phone on June 7th, describing it as the biggest leap since the original iPhone. The device, which now includes a high-definition video camera, video calling - dubbed FaceTime - and multitasking, goes on sale in Ireland next month, and will be available in 88 countries by the end of September.
Introduced in 2007, the iPhone has become Apple's top-selling product, with more than 50 million of the devices sold since its launch, even after users reported glitches and dropped calls with previous versions of the device.
The company and its carrier partners took a record pre-sales orders of 600,000 iPhone 4 devices in one day.
However, Apple is facing increased competition from Android phone makers, such as HTC, which rely on Google software. There are some 60 Android-based mobile phones, and according to research firm Gartner, Android overtook Apple in the North American market in the first quarter of the year. It believes the Google-powered phones could soon catch up with Apple globally. In a separate report, IDC said Android could beat Apple in terms of shipments by 2013, with 68 million devices predicted to be shipped that year.
Apple said this week it was delaying the release of white iPhone 4 models until the second half of July because of unexpected manufacturing challenges.
Additional reporting - Bloomberg
