rooting – Recovering files after the boot loader

I'm following this tutorial (sorry, it's in Spanish, if you need more information, let me know) and, as you can see, the boot loader step is getting locates before the backup copy step.
I went into the details of this boot loader step and did what is stated here and when my phone rebooted, I found that I had lost all of my files.
However, I could recover some of the contacts and apps, I think because of my gmail account. Is there a way to also recover files like pictures that I had in the phone memory? Maybe it's easier after being root? Thank you!