You can't directly mount the disk unless you're using on an iPhone 4 and below. Data recovery software won't be able to read the iOS root, you'll need to have utilities that specifically do so as it doesn't operate at a 1 to 1 level as a computer HDD.
For a full system image, you'll need professional utilities such as Elcomsoft and Cellebrite, basically a mobile forensic-like utility as you're on the iPhone 5.