I want to know if it's possible to get a "disk image" of the storage space on Android devices when they don't use external storage like SD cards.
I'm mostly interested because my kids factory reset my Kindle Fire HDX and I was hoping I could get a disk image (using something like dd in Linux) and then try to recover some of the user data like photos and videos (using something like PhotoRec, http://www.cgsecurity.org/wiki/PhotoRec). I've done this lots of times with SD cards and hard disks by simply mounting the storage device in a desktop running Debian, and executing something like:
# dd if=/dev/sdb1 of=image.iso
Then you can use PhotoRec and/or TestDisk, depending on what you want, to get useful stuff out of the image file.
Even some of my very old Android devices seem to allow mounting a storage device in this way (without removing SD card from the phone) and following this process. Unfortunately, it looks like many new devices that don't have removable storage (like my Kindle Fire HDX and my Nexus 5) only allow you to interface with a computer using Media Transfer Protocol (MTP) and Picture Transfer Protocol (PTP).
Can I use these protocols to get a bit-by-bit copy of the storage in the device? Is there a way to add the older storage device capabilities to new phones?