Question [Q] How to open Nexus 4 internal storage dump?

Hi guys,
I'm trying to recover some deleted files (I've tried some apps but they can recovery only some known formats, jpg, doc, contacts, I didn't find a generic one) so I made a full internal memory dump using this guide ->

Now I'm trying to use testdisk to recover my files but using it against the dump, it finds only one partition with no files inside.

How can I do this job? Did I make something wrong (excluding deleting things I need ). Dumpfile is about 15GB big.

Thank you!