I am not sure how many of you visiting this page are familiar with the presence and importance of the EFS thing that we are going to talk about today! Actually, I often hear people requesting to offer a solution of a problem that makes them unable to make a call, send a message, access internet or any connectivity related thing. Imagine a mobile phone without a network connection at all and you’ll then realize how horrible it is!
So, if EFS is so important a thing, it must be preserved so that you might be able to use all connectivity features of your device. This thing is found in all mobile devices which have an IMEI (International Mobile Equipment Identity) number assigned to it but the location and directory where it is stored might differ. On Samsung Galaxy devices, the IMEI and other connectivity data are stored in this particular folder that I have been mentioned several times so far.
Having read about the role of EFS on your Samsung Galaxy phone or tablet device, you must be a little more curious to know something more about it. EFS is a system directory that contains device specific essential information such as its IMEI, wireless device MAC address, baseband version, product code, system ID and NV data.
In case the EFS directory is corrupted or lost, your phone or tablet is sure to lose its IMEI number and wireless and network connectivity. You might ask how and why does the EFS data on your device might be lost or get corrupted? The answer is pretty simple and the reason might be a daring activity on your part. Sometimes flashing a custom Kernel (as reported by some users) and in most cases installing a custom ROM is responsible of the EFS data loss.
In this way, the EFS or IMEI loss is deeply related with what you do after rooting your Samsung Galaxy device. Keeping this thing in mind most of our ROM developers insert a script that automatically creates a backup of the EFS data on the external SD Card so that you might restore it back in case of loss or corruption. But it is certainly not wise to rely blindly on the wisdom of others. That is why, whenever we write installation tutorials for custom ROMs for Galaxy device, we warn users to backup EFS before indulging in any custom development activity.
Sadly, most people come to know about the thing called “EFS” only when it is too late. Once lost without being backed up, recovering it becomes very much like a wild goose chase. You might have heard or faced personally the issue when your device shows inability to mount EFS:
E: failed to mount / efs (invalid argument)
If you get this message on your phone’s screen, believe me you have got into a serious problem. Of course, there are ways to restore EFS data, but they are either not available for all devices online or they do not work at all.
It has been well said that “prevention is better than cure” and this saying hold quite true in this case too. Therefore, the first thing that one must do just after rooting and installing a custom recovery one’s device is to backup the EFS and the stock rooted firmware. For more enlightening tips, do not forget to read the following article:
As the very title of this article says, we are going to tell about a very easy solution to backup the EFS on your Samsung Galaxy device. It is a simple but wonderful tool developed by XDA member LiquidPerfection that makes this job a plaything that can be done by anybody. The tool is called EFS Professional and it supports most Galaxy range of Android devices from Samsung.
The latest version of the software also supports Samsung Galaxy S4 International (GT-I9500), Galaxy S4 LTE (GT-I9505), AT&T S4 (SGH-I747), Verizon Galaxy S4 (SCH-I545) and others. I have also tested it on Galaxy S3, S2, Note 2 and Note 10.1. Besides, EFS Professional works with other Galaxy phones and tablets too.
Before you can backup your device’s EFS data safely to your device and PC both, here are a few things that must be taken care of:
So, do you think you are ready for action now? Make sure you have made all preparations detailed above. If yes, let’s get started now.
Having backed up your EFS data, you might take a calm breath and feel a sense of security but it is also important to be familiar with the method how you can restore it back to your Samsung Galaxy device in case you lose it.
Your Samsung Galaxy device’s EFS/IMEI should now be restored back to its original location. Dia *#06# on your phone’s keypad to check it it has IMEI number or not.
There is yet another handy utility for backing up the EFS and NV data on your Samsung Galaxy device. It is a free app and called kTool. Since it is a phone-based utility, it is easier to use. It supports almost all Samsung devices except the Qualcomm based LTE devices.
Needless to say that the app demands root access on your phone and besides backing up and restoring the sensitive EFS/IMEI/NV data, it can also perform various other tasks like-
Note: In case you notice that your phone’s lockscreen is not working properly after backing up the EFS, go to Advanced Settings in the kTool menu and enable “Alternate EFS Dump Method”.
Download Latest kTool:
You might be already familiar with Aroma. It is a custom recovery based installer that can install custom mods, ROMs and scripts. Unlike CWM or TWRP, Aroma Installer allows users choose from various options and provides customized installation. If you have a rooted phone with either of the above-mentioned recoveries installed on it, you can download the Aroma Installer from below and backup your phone’s EFS data and, if needed, restore it later.
Download one of the following Aroma installers-
The users who own a Samsung Galaxy device with root access but no custom recovery can use a free app called Terminal Emulator to backup and restore EFS on their device. Here is how it can be done:
dd if=/dev/block/mmcblk0p3 of=/storage/sdcard/efs.img bs=4096
dd if=/dev/block/mmcblk0p3 of=/storage/extSdCard/efs.img bs=4096
Now here is how you can restore the backed up EFS using Terminal Emulator:
Launch the app and type the following command depending on the location of the EFS.img file:
dd if=/storage/sdcard/efs.img of=/dev/block/mmcblk0p3 bs=4096
dd if=/storage/extSdCard/efs.img of=/dev/block/mmcblk0p3 bs=4096
In case the terminal Emulator method (using the above commands) does not work for you, it might be due to the location of EFS partition on your phone. To fix that, you can try this:
dd if=/dev/block/mmcblk0p3 of=/storage/sdcard/efs.img bs=4096
You can also backup EFS using custom recovery tools like TWRP and Philz Recovery. I do not think you need a guide to do that. Here is a screenshot of TWRP from my Galaxy S4. The option is found under Backup head.
Though this post already has several solutions for backing up and restoring EFS/IMEI on Samsung Galaxy devices, we keep looking for even easier methods. The Samsung Tool by ricky310711 from XDA forum is yet another smart tool that lets you backup your phone’s EFS in .img format to your phone’s internal or external storage. When required, you can restore the EFS using the same tool.
The backed up EFS file is saved to the following location Storage/ extSDCard/ Samsung Tools. We tested the tool on Samsung Galaxy S4 and Note 3 and it worked fineBesides, Samsung Tool also works as a reboot manager app. It lets you reboot your Samsung device into Download and Recovery modes without pressing the hardware keys.
Apart from the tools discussed in this article, you can find many others that work with specific device models. You can try them too! With a hope that it proves helpful to the community, allow me to wind up here. If you have question or problem related to the topic, feel free to leave a comment below. Cheers!