Google Play Protect warns OnePlus 3/3T owners on OxygenOS 5.0.1 that FactoryMode may be harmful.

The app is a diagnostic tool used during device manufacturing and after sales support.

It was previously known as EngineerMode and was exploited to gain root access to OnePlus devices.

You might remember that in November, OnePlus updated the 3 and 3T to Android 8.0 Oreo. The update brought a bunch of new features and a few bugs, too. To squash them, OxygenOS 5.0.1 started rolling out near the end of December. It fixed bugs, added support for aptX HD, brought a new Wi-Fi hotspot device manager, added an adaptive mode screen calibration, and included the December security patch.

Editor's Pick OnePlus phones include an easily exploitable backdoor (Update 2: Qualcomm responds) Update #2 (11/15) 14:09 EST: Qualcomm has reached out to Android Authority to clarify some details on the EngineerMode app. A Qualcomm spokesperson says: After an in-depth investigation, we have determined that the EngineerMode app in question …

But despite all the dead bugs and new features, a new issue has popped up. Google Play Protect is now warning users running OxygenOS 5.0.1 that an app called “FactoryMode” might be harmful. Google Play Protect prompts users to uninstall the app, although users can keep it even though it may not be safe.

What is FactoryMode? The app used to be called EngineerMode and is used during device manufacturing. It is generally used to test phones before they leave the manufacturing line, but after sales support uses the app as well. You can safely remove it with Google Play Protect, but you might have issues if support staff need to use it in the future.

The app was the center of controversy in November due to its role in granting root access to OnePlus devices. A security researcher was able to gain root access to OnePlus phones using an exploit in the app. OnePlus later patched the exploit and has since changed the name of the app.