How to backup the EFS Folder - IMEI

In this tutorial I'll show you the way to backup EFS folder and restore it, in an fast and easy way

¿Why should I do a backup of EFS folder?

If you are a Custom ROM lover, this is a mandatory step, because the EFS folder contains unique and very important information, that allows your device to connect to a mobile network, because it contains your IMEI (a unique number given to every single mobile phone) you can lose that information when you are flashing your cel phone, so here you'll learn how to make this backup.


  • Be a root user
  • Download Root Explorer (payment)  buy here , alternative to ROOT File Explorer FREE here


  1. From the explorer we choose, go to the root of our cell phone and locate the EFS folder.
  2. Once we found it, copy it to our micro SD (it's strong recommended to make another copy to our PC).
  3. To make the handling easier of our folder, we can zip it and copy it along with our backup before starting.

Once the backup has been completed and before start to try new Custom Roms, we have to make a last security backup, ¿what are we talking about? to make a bakup of the original ROM before replacing by another one, so this way we could reverse the changes made, if we are not satisfied with them, I'll show you that in this tutorial here


  • Verify if yourGalaxy S3 have risk of Brick with eMMC Brickbug.
  • This tutorial is only for Samsung Galaxy I9300.
  • You lost your factory garanty if you create Super User
  • Youtube, Soluciones Windroid and Proyecto Byte will not be liable for the improper use of this information because it may result in the damage of the device.

Esta entrada también está disponible en: Spanish

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