Custom ROM install - Firmware Backup
I have to install CM11 on three different smartphones, being Galaxy SII, S4 mini and another one.
I wish to ask how can I create a firmware backup of default factory setting phone so that if I wish to go back to original device I can restore the Samsung Firmware.
I have never done it though I am trying to document myself on the Internet.
What are the tools and the steps in creating a firmware backup? Obviously, I will factory reset the device before doing so.