Consumer Reports said on Wednesday its tests confirmed that putting Apple Inc's new iPhone into a case fixes the reception problems that some users have experienced.
The influential publication said using a Bumper -- a $29 frame-like cover sold by Apple -- prevents a drop in signal strength that occurs when the iPhone 4 is held in a certain way.
The finding confirmed what bloggers and others said about using a case with the iPhone, which went on sale last month and became Apple's fastest-selling product ever.
The Bumper solves the signal-strength problem, Paul Reynolds of Consumer Reports said in a blog posting.
So does a piece of duct tape, as we reported earlier, or just being careful how you hold the phone. But these options all put the onus on consumers to solve or pay for a fix. We're still calling on Apple to provide an acceptable free solution to the iPhone 4's signal-loss problem.
Consumer Reports generated headlines on Monday when it said it could not recommend the iPhone 4 to buyers due to reception issues.
Apple has blamed the problem on a software glitch that overstates network signal strength. But Consumer Reports has called into question that claim, and others say the design of the device is the real issue.
Analysts say Apple's shares were pressured this week by the bad PR surrounding the iPhone 4, and the company's failure to respond and put the matter to rest.
Shares of Cupertino, California-based Apple rose 0.4 percent to close at $252.73 on the Nasdaq.
(Reporting by Gabriel Madway)