If you have ever wanted to run a hardware test without a third-party app, check your IMEI number instantly, or calibrate your sensors, this guide is for you. While most codes are safe, some (like the factory reset or NVRAM codes) can erase your data or damage your radio calibration if misused. Proceed with caution.

Before we start, a quick warning. Some of these codes grant access to deep system settings (like rooting or bootloader unlocking). If you don't know what a specific engineering setting does, Changing random values in the engineering menu can brick your device. Proceed with curiosity, but caution.