Apple appears to have a serious hardware problem on its hands as the internal sensors of its new flagship phone, the iPhone 5S, are not reporting accurate numbers.

Numerous reports on Apple support communities indicate that people believe the sensors that report level, motion, and acceleration seem to be reporting incorrect information. And a detailed Gizmodo test indicates that indeed, they are “all screwed up.”

“My iPhone 5S is off by 4 degrees when using the level on its back (screen up). I had an iPhone 4 and 4s that I upgraded to iOS 7 and both were perfect, but the 5S is off,” an iPhone 5S owner reported in Apple’s support forums. “Holding it vertically it is also off by 1 or 2 degrees.”

I tested the iPhone 5S myself and found that the iHandy Level app indicates that a surface is level when the phone is clearly at an angle, and the Gyroscope app reports pitch and roll numbers that indicate the phone is on a slope when actually, it’s on a flat and level table. My older iPhone 5, other the other hand, reports numbers that are much more accurate. Both phones are running Apple’s latest version of iOS 7.

Here’s just one example, in which the iPhone 5S reports 2.3 degrees differently than the iPhone 5:

Image Credit: John Koetsier

This has real-world implications, as Gizmodo points out, and it’s not just that your shelves or paintings will hang crooked (of course, I’d never use an iPhone sensor to hang a painting or install furniture). Games also rely on those sensors, and players who want to beat the game or beat their friends may run into trouble — like I did in Real Racing 3.

As you can see, when the phone is flat on the table, the car turns left and hits the bumper. Clearly, the sensor is telling the game that the gamer is trying to turn left:

Not all the sensors are reporting bad data — at least not on my phones. The same iHandy Level app that reports incorrect numbers for level on the iPhone 5S, reports almost identical numbers to the iPhone 5 version for plumb (straight up and down):

The internal gyroscope, however, that measures pitch and roll and yaw appears to be also affected by whatever gremlin is troubling the new iPhone 5S. As you can see in the image below, the white iPhone 5 on the right reports zero degrees of roll and -1 degree of pitch. The space gray iPhone 5S in the red case on the left reports one degree of roll and 3 degrees of pitch — 4 degrees off.

(The yaw numbers aren’t relevant here, as they relate to the individual motions of the phones prior to being placed on the table, and not to their current orientation.)

While perhaps not quite as severe, there’s still a slight and unexplainable difference. The question is what could be causing this. It’s unlikely that software is the issue here, as I’m running iOS 7 on both phones and the same apps. There would appear to be a hardware issue at fault, which is a big problem for Apple.

Because, after all, how do you fix shipped hardware?

Essentially, you can’t, unless you recall it or issue a software fix that sort of kind of somewhat corrects for the bad data — assuming Apple engineers can spot a pattern in reported sensor data that can be adjusted for. Which leaves equally unattractive options such as Apple just telling people to live it it (and hurting its premium image in the process) or issuing some kind of credit to affected customers.

I have asked Apple for a comment and will update this story when I hear more.