Windows phone users should know to choose "Settings" > "About" > click "Reset Phone" to complete the phone reset operation. In fact, there is a more convenient way, that is in the dial input # #777 #.
After entering # #777 # You will receive the system pop-up reset warning prompts without clicking on the other keys. As shown in the screenshot above, this is a special reset that will preserve the map data, retail mode content, custom data, and network settings while restoring the phone's factory settings. This means that the Reset method is especially useful for users who are not covered by a wireless network in the vicinity, because they will not have to download more than 100 MB of maps after resetting their phones.
However, it is important to note that this reset method is only applicable to some Windows Phone models, does not apply to the model after entering # #777 # will have no response, and this feature is incompatible with the emergency call function.