How to Manually Backup the EFS and NV Data on Samsung Galaxy S5

In the following guide we’ll tell you how to manually backup the EFS and NV data on Samsung Galaxy S5. Every Samsung device has its own IMEI, Wireless MACaddress, product code, system ID and NV data. If some how one these files are corrupted during flashing a custom rom, it will result in Null IMEI, Not Registered on Network and Unknown baseband so to avoid these issues it would be better to Backup the EFS and NV Data.

Before proceeding any further you need the following:

# 1: Samsung Galaxy S5

# 2: Your device must have root permission. [ Root Guides ]

# 3: Battery must be charged 60%.

How to Manually Backup the EFS and NV Data on Samsung Galaxy S5 [SM-G900F/T/P/A/I/M/W8 variants ]:

Step 1: Download the Terminal emulator for Android from Google Play Store.

Step 2: Now open the app and write the following command in the prompt. [ Give Root Permission if you haven’t already ].

su

Step 3: Now type the following commands one by one in prompt.

dd if=/dev/block/mmcblk0p12 of=/mnt/sdcard/efs.img.ext4

dd if=/dev/block/mmcblk0p13 of=/mnt/sdcard/modemst1.bin

dd if=/dev/block/mmcblk0p14 of=/mnt/sdcard/modemst2.bin

Step 4: After the process is done, you’ll find the following files in your root of internal memory.

efs.img.ext4 (20 MB)

m9kefs1.bin (4 MB)

m9kefs2.bin (4 MB)

m9kefs3.bin (4 MB)

Step 5: Now Copy all the files to a secure location.

How To Restore EFS on SM-G900F/T/P/A/I/M/W8 variants:

Step 1: Download the Terminal emulator for Android from Google Play Store.

Step 2: Now open the app and write the following command in the prompt. [ Give Root Permission if you haven’t already ].

su

Step 3: Now copy all the EFS backup files to the root of your internal memory.

Step 4: Now execute the following commands one by one.

dd if=/mnt/sdcard/efs.img.ext4 of=/dev/block/mmcblk0p12

dd if=/mnt/sdcard/modemst1.bin of=/dev/block/mmcblk0p13

dd if=/mnt/sdcard/modemst2.bin of=/dev/block/mmcblk0p14

Step 5: After all the commands were process successfully reboot your devices to apply changes.

Source: XDA