Samsung Galaxy S7 and S7 edge are in the market for quite long time now and Android geeks are Flashing Custom stuff on their devices as root privileges are already been granted to Galaxy S7 devices. Also Custom recovery is also available for S7 and S7 edge so now when it comes to Flashing Custom stuff on an expensive Android device you have to make sure nothing goes wrong with it. You can lower the risk level by backing up your system data different partitions and also personal data like contacts. In this way you can play it safe and if something goes wrong during tweaking the back up will hold your back.
If you are first time Galaxy Smartphone user, you might not be aware of EFS partition, Galaxy devices use EFS partition for maintaining the IMEI, NVRAM, WiFi / Bluetooth Mac addresses and Radio data. In case you mess up with this sensitive EFS partition everything else will mess up with you, it may destroy the GSM connectivity which means you are now unable to make calls, send texts and things like null IMEI will happen. Wait! Did I scare you? well no need to be, there is a simple way to avoid all this just do a little effort and make a backup of EFS and other sensitive partitions which I will be telling you below, follow the guide.
Backing up EFS partition will require you to root your device which I am sure you already did as you are going to flash custom ROM. So, without any ado lets move to the main thing Backing up EFS and restoring IMEI.
This guide is only intended for Samsung Galaxy S7 and S7 edge Variants
Galaxy S7: G930F, G930K, G930L, G930X, G930S, G930W8, G930FD,
Galaxy S7 Edge: G935F, G935FD,G935X, G935K, G935L, G935S, G935W8
Download the File
Wanam's partition Backup App | link
A) Backup EFS partition and IMEI on Galaxy S7 and S7 edge
1. Make sure your S7 is Rooted otherwise it won't work.
2. Download and install the Wanam's partition Backup App from the link provided above.
3. Now launch the App and allow SuperSU permissions.
4. In the app menu click the small settings button on top and select the Format ( .tar or .img ).
5. Now below from the partitions list select EFS and Radio partition.
6. Now at the lower right corner of your screen you will see an arrow click on it.
7. A message will appear now Tap Backup here. The backup will be present in your phone's internal storage in folder "Partitions Backup", That's it.
B) Restoring IMEI/EFS partition on Galaxy S7
Now if you have corrupted the EFS partition during flashing accidentally, you can back it up using the same app.
1. You should have the backup of your EFS partition to restore it.
2. So, now launch the app and on top right corner tap 'options'
3. Now select restore a partition then locate and select radio or EFS .img files from the internal storage inside backup folder.
4. After selecting follow the on-screen instructions and that's it.
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