How can I determine which block device corresponds to internal memory?

Question

Premable: My MP707 phone gave me an "overheated battery" panic message earlier in the summer, adn told me to take out the battery immediately. (It had been sitting in the sun, and was probably just confused about the source of the heat, but I didn't think of this at the time, alas.) So I opened it up and took out the battery...without a shutdown first.

The next time I started it up, I got a warning about internal storage being damaged, and did I want to reformat it. Note: internal storage, not the SD card! I found that images and recordings I'd made were no longer accessible, and the voice recorder didn't want to function because it couldn't find a place to store the recordings.

Not long after, the phone started shutting down at random, and then wouldn't start up at all. I ordered a new battery, and went back to using my old phone.

A few days ago, I picked up the MP707 and it turned on just fine! (Still gave me the damaged memory warning) And as far as I can tell -- I'm a newbie in this phone stuff -- the internal storage seems to have gone missing.

The meat of the question: Following the advice here How can I recover a deleted file on android I managed to root the phone, install a terminal program, and start poking around. I'd like to do a raw copy of that internal memory, in hopes of recovering one or two things. But the first instruction is "Find out on which block device the file was on. Via mount". Well, mount tells me this:

(I can't figure out how to copy/paste from VNCLite...sorry).

Can anyone, looking at this, guess which mount point corresponds to internal memory, or tell me how I might determine this?

Answer 1

As Izzy said INTERNAL STORAGE usually refers to /data, it's the partition where apps are installed and where they keep their private data.

Also /storage/sdcard0 could be part of internal phone memory, called PHONE STORAGE it's an emulated sdcard (I can't tell if in your case that's emulated sdcard or real)

To make a raw backup of your data you need to know which block contains that partition, you can check it with this command:

cat /proc/emmc

Result should contain lines like this:

emmc_p7: 001a4c00 00300000 "usrdata"
emmc_p8: 004a4c00 0358dd00 "fat"

This gives you partition number p7 , now you can use this command to list blocks:

 cat /proc/partitions

Result should contain:

  179        7    1572864 mmcblk0p7
  179        8   28077696 mmcblk0p8

In this case to backup /data aka emmc@usrdata contained in mmcblk0p7 block you can use this command:

dd if=/dev/block/mmcblk0p7 of=/storage/sdcard0/usrdata.img

Supposing sdcard0 is working properly and there is enough space. After that usrdata.img can be mounted in a linux box with:

sudo mount -t ext4 -o loop usrdata.img ./folder

P.S. You might check how to use adb so you can open a console on your computer and issue commands to your phone connected with usb.

Answer 2

"Internal storage" usually refers to the /data partition. Unfortunately, your output is a little "cropped" and thus not easy to read (might be helpful to copy/paste it as text). It should correspond to the line reading

emmc@usrdata /data ext4 rw,relatime,noauto_da_alloc,data=ordered 0 0

which unfortunately doesn't show the block device (unless emmc@usrdata can be addressed as such; guess the missing character in front is a /?). Interesting fact to see is your /system partition is mounted read-write as well – usually it's mounted read-only, so it shouldn't be affected by such trouble. /cache can be ignored (or simply wiped/formatted without losing any data, as it only holds "temporary stuff").

The */vold/* devices usually refer to your external SDCard, just for completeness, and entries using a file system like tmpfs or devpts are also safe to ignore (they are created on-the-fly on boot), similarly for rootfs, proc, sysfs, and AFAIK also cgroup. Using this rule, there's not much left to "backup and copy" ;)