Android
Reset to factory firmware of Android phone is performed using corresponding setting in menu or by keyboard shortcuts (if it is not possible to turn on the phone). To reset the firmware of the phone, go to menu "Settings" of the device. Then click "About device" and select "factory Reset". The name of the menu item to call to reset may vary depending on operating system version and manufacturer of the device, which made changes to the standard firmware. If necessary, enter the security code to reset software, and then confirm the operation.
If you want to return phone to factory status in case of impossibility of its full launch, hold down the key combination the phone, which can be described in the instructions for use of the device, on specialized forums or on the official website of the device manufacturer in the technical documentation. Most machines drop the version of their operating system and return to factory settings when using key combinations unlock (enable) the menu button and volume down. It is worth noting that some phones to factory reset using the volume up key. The power button can be released after the launch of the smartphone, and the volume keys and the menu should be pressed for a few seconds before the start of the formatting process.
iPhone
For resetting iPhone you can also use the corresponding menu item. To do this, go to "Settings" - "General" - "Reset - "erase all content and settings". Double-confirm the action and wait for the return phone to factory condition.
You can also reset the device using iTunes. Connect your phone to your computer and open iTunes. After that select the device name in the upper right corner of the program. In the "Overview" section and click on "Restore". Remember that resetting the firmware will lose all saved settings and data, but because before surgery it is recommended to make a backup.
Windows Phone
Reset the firmware of your Windows phone also performed using the corresponding function available in the settings. Click "Settings" and go to "device Information", then select "factory Reset". Double-confirm the transaction and wait for notification of completion of formatting.
Some models of Windows phones can be returned to factory settings without the need to switch on the device. To do this, hold down the volume down button simultaneously with the power supply. Release the power button. Once you see the logo of the phone, release volume down key. Then click volume up, volume down, power and then volume down. After that, wait for reset and you are prompted on the screen.