You might not want to use your iPhone 5s to find your way out of the woods just yet.

A number of users are reporting that their iPhone 5s compass and level are showing incorrect values when placed on flat surfaces. It might be a hardware issue, leaving Apple with a costly hardware recall or replacement issue. The problem could also point to a software snafu that needs speedy patching.

The problem was first spotted on by “tharepairguy” on a forum thread over at Mac Rumors. He set his iPhone 5s and his iPhone 4 to magnetic north. The iPhone 4 reads 179 south, while the iPhone 5s reads 165 south. His car compass confirms the iPhone 4 reading.

He then checked the level app on each phone. The iPhone 4 showed a surface to be level, as did two other Johnson analog levels. The iPhone 5s? -4 degrees.

Unscientific tests in the Cult of Mac newsroom show the accuracy is off the charts. And not in a good way, as you can see from the photo above. We’ve got a Casio watch compass then an iPhone 5s and an iPhone 4 lined up together, and something is definitely not accurate.

Back at the forums are four pages of posts with a large number of users reporting similar differences in readings between their older phones and their newer iPhone 5s devices. A few folks chime in saying this is no big deal, but for the majority of posters, it’s a big enough deal.

If the gyroscope is off, the consequences could be as minimal as having racing games not work properly: a couple of posters say their cars drift to the right when the iPhone 5s is set on a flat table. On the other hand, an incorrect compass reading could, in fact, put someone’s life in danger if they use their iPhone 5s to navigate with.

The original poster says he got a call from Apple support telling him to recalibrate the sensor by plugging the iPhone 5s into a wall charger, turn on Do Not Disturb and to not touch the device for over 90 minutes. Other forum members report trying this (one for over three hours) with no positive results.

Apple did not immediately respond to a request for comment.

Source: MacRumors Forum