Reported sensor issues with Apple’s iPhone 5s are being caused by a new and allegedly undercalibrated accelerometer in the device, according to a new blog post. Eagle Jones, CEO of developer RealityCap, writes, “Quite definitely, the answer is that these issues exist due to hardware design.” Jones points out that a recent Chipworks teardown identifies the 5s accelerometer as a Bosch Sensortech BMA220 — Apple previously used parts from another manufacturer, ST. The Bosch accelerometer has a different bias spec than the previous ST part, and the wider bias range makes it more likely that the sensor won’t be level. Jones writes that app developers can incorporate a calibration process within their apps to get a correct reading, or Apple could update iOS to include a proper calibration profile for the new sensor. So far, Apple has been silent on the issue.