How to organize data transfer from phone to phone?

Question

Android

Greetings. Not so long ago I had a need to transfer data from one Android phone to another, but I came across such an interesting thing as root access to the phone. After some torment, I abandoned this matter, but I became interested in this: There is a Titanium Backup program for backing up my application data, for example, I'm reading a storybook and I want to transfer the "saved progress of the read" to another phone, but in order to do Titanium Backup needs root permissions to back up this data. And now attention to the question: how does the program itself that works with this data, for example, again a storybook, get access to this data if it works not from root, but from some other user, and why I just can’t find the data file with "
Sorry for the confusion of the presentation, it's just that the situation is very interesting and not entirely clear to me ...

Answer 1

The reader program is the owner of its data directory, so it has no problems accessing its own data, but there may be restrictions on accessing someone else's.
An ordinary user is limited by the sandbox allowed to him, he has no right to look into files to other users (programs).
ROOT spat on almost all the rights and looks what he wants.

Answer 2

Only a program installed by the manufacturer (or the seller, some stores and resellers install their own crapware and adware, some are so cunning that resetting to factory settings does not save) can have access to other people's data located in the / data directory, otherwise access is only to their own data. Also, applications have access to / sdcard / ... internal memory and to a memory card, if it is connected, but for this the application will require the appropriate permissions (accepted by the user at startup)
root is not required, you just need to run recovery on the cellular (launched by simultaneously pressing volume and power buttons, after turning off the cell phone), you can almost always make a backup copy from there, if it is not encrypted, you can extract the necessary data from it or simply restore it on another cell phone.
True, official manufacturers install a castrated application as a recovery, which, at best, will allow you to install an official update and that's it.
Therefore, you need to find the recovery version (in the form of a xxxx.img file) and run it on your phone (you don’t even need to flash it, but you may need to unlock the phone - detailed instructions often differ by model and manufacturer). You need to use the adb and fastboot utilities - official platform-tools from google sdk (download from Google, though you will get a bunch of development utilities with it, they are lying separately on warezniks)
Fastboot mode - phone mode for low-level access to the phone, does not have an interface, the phone screen will display a drawing of a repairing robot bunny, it is launched by another volume button at the same time as the power button, carefully read the instructions for your phone, otherwise you can get a brick. But in most cases it is suitable:
this command will not change anything on the phone, but simply start the recovery (I recommend twrp) You may
first need to unlock the phone:
almost anything, flash custom firmware, add / remove applications, etc.
ps but some manufacturers (for example, xiaomi) made a goat for some new models, and to unlock it, you first need to link the phone to the mi account and then tearfully ask the Chinese for firmware (for instructions on the Internet, read w3bsit3-dns.com), if you are lucky in two weeks it will be unlocked for you remotely.
I was 'lucky' twice - my xiaomi redmi note 3 pro phone was locked, but there was a crack for it (patched official assembly, after flashing it, oem unlock worked and I was able to change firmware)