If you are fond of custom ROMs and modifications, then it would be a nice and wise decision to backup EFS (IMEI) and modem partitions of your Android mobile device before flashing custom modifications.
Note: This tutorial is not intended for those who have already lost their EFS (IMEI) partitions. We will be publishing a separate post for them very soon. If you are one of them, comment below or subscribe to our newsletter to get updates on the same.
Before getting into the detailed procedures, lets learn about the EFS and modem partitions and the problems that could arise when someone messes up those partitions in an Android device.
EFS stands for Encrypting File System. It is an important part of Networking and Communication in an Android mobile. It also contains device IMEI (International Mobile Equipment Identity) data, which is necessary for network communications.
For more information, visit Encrypting File System – Wikipedia.org
When installing custom ROMs, it is always advised to backup EFS (IMEI) to a safer place. Because these are the places where you might loose or even corrupt the data. When you lose the data present in these places, you may no longer be able to use your smartmobile for communication, reducing the device to just a multimedia toy.
A modem is also referred to as a radio or a baseband. It is a driver that modulates and demodulates the carrier network signals. It is used to control network signals and to switch between GPRS, 3G and HSDPA in a mobile device. It does not control Wi-Fi or the switchover between mobile signals and Wi-Fi.
For more information, visit Modem – Wikipedia.org
To know your mobile modem details, switch on your Android mobile and go to Settings > About phone > Baseband version. When you mess up your mobile modem, network problems arise.
Now, as you know the importance of your mobile EFS (IMEI) and modem partitions, you should and must backup EFS and modem partitions of your Android mobile before installing any custom modifications.
Backup EFS (IMEI) and Modem Partitions of Android Mobile Devices
Note for GT-S7262 users: EFS, Modem and Modem 2 partitions of Samsung Galaxy Star Pro/Plus GT-S7262 mobile are interlinked for unknown reasons. Hence, you should backup all the 3 partitions to restore them whenever you encounter network related problems like IMEI lost, yellow screen etc.
- Android mobile with root access
- File explorer with root access, preferably ‘ES File Explorer’
- External or internal memory card
- Install Partitions Backup & Restore, ES File Explorer apps from Google Play Store on your Android mobile.
- Grant root access to both the apps.
- Launch Partitions Backup app and click on Settings icon present on the top right corner of the app.
- Select External SdCard as backup path (if SdCard available) else select Internal SdCard, then select Highlight all related IMEI/EFS partitions. Now select Raw partition image (img) as backup format.
- Click on back button.
- For GT-S7262 users: Select EFS, MODEM, MODEM2 partitions (yellow colored).
For others: Select EFS and other appropriate partitions (yellow colored).
- Then click on the Download button present on the bottom right corner of the app. The app will now backup efs and related partitions to the selected memory card.
- Launch Partitions Backup app and click on the 3-dot button present beside settings icon.
- Select Restore a Partition option and then OK option.
- Now select ES File Explorer option and then select Just Once option.
- Browse to memory where the backup is present and select Partitions Backup folder.
- For GT-S7262 users:
- EFS: Select efs backup file from the folder and then select efs (mmcblk0p3) and then click on Restore.
- MODEM: Repeat steps 1,2,3,4 and then select modem backup file from the folder and select modem (mmcblk0p7) and then click on Restore.
- MODEM2: Repeat steps 1,2,3,4 and then select modedm2 backup file from the folder and select modem2 (mmcblk0p11) and then click on Restore.
- For others:
- EFS: Select efs backup file from the folder and then select efs (xxxxxxxx) partition, where xxxxxxxx is the partition name. Remember to select the exact target partition as the input backup file. If everything is in correct place, click on Restore.
- Repeat the similar steps for other partitions (if any).
- Reboot your mobile.
Note: If you think that you have made a mistake while restoring partitions and your mobile is now stuck at bootlogo, then reboot your mobile in recovery mode and restore your partitions from CWM recovery or TWRP using the backup files present on the memory.
That’s it for today. Hope you will find this small but useful guide useful. Share it with your family and friends.
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