CWM (ClockworkMod recovery) is a custom recovery menu for Android devices. With it, you can install unofficial firmware, reset your phone to factory settings, create backups, and much more. This “recovery” is available to control only with the mechanical keys. That are the volume buttons and the power key.
Install CWM Recovery on the smartphone is possible through a separate application ROM Manager. But this requires root rights or a computer. In the second case, a special Android SDK platform is used. This recovery menu significantly expands the device’s capabilities and, most importantly, allows you to roll back to a previous version of MIUI.