What is a NANDROID backup ???
When you are going to flash a custom ROM on your phone everywhere people are shouting take a NANDROID backup… take a NANDROID backup… what exactly is that? The name is there from the CWM days as far as I know. Basically the phone has an internal storage or even the microSD cards which are basically NAND flash storages. As we are dealing with Android, I guess some developer have named the storage backup process to NANDroid backup.
Basically a NANDROID backup means creating a backup of all the required partitions on your Android device. Android has a partitioned layout which has a boot partition, recovery partition, system partition, data partition, cache partition etc. When we take a NANDROID backup we are actually copying all the data in each partitions as a single file. you know what I mean to say… I mean the boot partition will be captured in a single file called boot.img, similarly the system partition in system.img and so on. This way the backup and even the restoration process gets much easier for the end user.
This feature is mostly missing on stock Android devices and you will only get it on CWM, Philz, TWRP or Cyanogen recoveries.
What is the benefit of having a NANDROID backup ???
you can think of a NANDROID backup as a SNAPSHOT of your current phone’s state. Lets say you have installed many apps on your phone, have many messages, contacts, etc… everything will be there as it is. So, you have the state of your phone on a given point in the time line. Basically this is ONLY helpful if you are trying a new Custom ROM which is buggy but you want to fall back again to your old ROM whether it be stock or any custom ROM.
The reason being, you are keeping all the backup data as a single file which can only be read by the recovery and to restore only. You cannot extract any other data lying in those backup files.
A nandroid backup will not be helpful if you are planning to migrate to a different ROM permanently. What I mean to say is, lets say you are flashing a Custom ROM which you already know that is stable and you can carry on using the new ROM then this nandroid backup will not be helpful. Instead you need to use Titanium Backup or Backup all data individually and then migrate all the data to the new ROM.
How to take NANDROID backup on a TWRP recovery:
Step-1 First, reboot your device to recovery mode.
Step-2 Now, on the TWRP home screen click on the Backup touch button.
Step-3 On the Backup screen, select all the partitions which you want to keep and then swipe the touch button at the bottom of the screen to take backup of the complete ROM with your data.
- The boot and system partitions are the basic backups needed to boot the system and hence are the must needs.
- Just to help you understand, A NANDROID backup is only helpful when you have the current Data partition which contains all the Applications, Messages, Contacts etc. Otherwise you can always flash the same Custom ROM from a zip file and go back to the initial stage but you will miss the current data.
- The Cache partition is just an add-on, without which there will be no impact and the system will re-generate the cache from the data that you have. If you have the cache partition the system will boot faster that’s it.
- The PDS partition basically keeps your IMEI, modem information and all which does not affected as part of a custom ROM flashing. But it is always a good idea to have this for the first time you backup.
- First of all see the options covered under the red rectangular box. Make sure you have done the same thing before taking a backup.
- Enable compression option will save some space by compressing the data. Don’t panic… even after compressing your data does not change and the Restore algorithm knows how to uncompress and extract the data.
- Don’t check the Skip MD5 generation during backup option. This is useful when you will go for a restore. Basically the MD5 hash data will confirm the backup that you have is really valid and not corrupted in-between.
- Definitely don’t check the Disable Free Space check option. If you will check this option then the TWRP will not check how much size you are taking backup and how muxh space you have on your phone or microSD card. See the example below to understand more on this:
- See the Storage: Internal Storage (2417) that I have marked on red with an oval box. Basically it says that I have 2417 MB of space left on my phone. If you see closely to the data partition that I am going to take a backup itself is of 5422 MB (marked on a blue box) which anyway is not going to fit in my phone’s storage. This is where you need to be careful and make some space before you take the backup. If you disable the Free Space Chcek option then you will face problem here.
Now if everything is OK then go ahead and take a backup. Move the backup from your phone or SD card to a PC or some cloud space.