MTK Engineer Mode 3.3.2 [free]

Only for phones with MEDIATEK processors! Not for Snapdragon, Exynos, Kirin, etc.But if you use a non-MTK phone, you can dismiss the incompatibility dialog that appears at the beginning and only use the "Android Test"
button
MTK Engineer Mode is a secret menu on your MTK smartphone, in which you can configure and do test of Hardware and Software, modifying the factory values.
You will have access to:
- Telephony
- Connectivity
- Tests and hardware settings (Camera, TouchPanel, Vibration, Audio ...)
- Tests and Location settings
- Log and Debugging
- Software Settings
- OthersVisit the XDA thread: https://forum.xda-developers.com/android/apps-games/app-mtk-engineer-mode-t2975528

• 12/30/2018: MTK Engineer Mode 3.3.2
• 06/18/2018: MTK Engineer Mode 3.2.0
• Report a new version