Database Users

[GUIDE] Backup your /efs folder before flashing any ROM (IMPORTANT!)

Hi everyone!
The reason why I post this threat is that there is no clearly mention about the /efs folder in the rooting/how-to guides in here. In my opinion, it's the MOST IMPORTANT thing to know for all Samsung devices with Android OS before flashing any custom ROM. There is a really good threat posted in Original Android Development by Rawat, which I'm going to quote right here. Unfortunately, it's not a sticky threat so it's gone somewhere deeper in the forums.
I really beg you for a sticky of this thread, or Rawats to prevent all new users of damaging their phones.
My point is: many of you can agree, the /efs folder is very sensitive. If it get corrupted and you have no backup of it, well.. let's just say it's nearly impossible to get you phone working again. It contains your IMEI number and some other important things! There have been some situations when it get corrupted after flashing some ROMs. Without a backup, your IMEI is gone. The only way to get your phone working again is to send it back to Samsung Service.
Here is the guide, originally posted by Rawat! Thank you very much:
This guide is based on a guide by Candanga on the i9000 forums, and some commands from supercurio
Please hit thanks on their posts and show them some love for the write up.
-----------------------------------------------------------------------------------------------------------------------
I’ve compiled a quick guide to instruct how to make a copy of the /efs folder. I’ve found in many threads suggestions about backing up this folder but the methods itself are very general. Most of the times they suggest to “root and copy the folder” with Root Explorer or similar, but usually it’s not that easy or it just doesn't work for everyone.
This guide ASUMES you have read this Excellent Guide by Darkstrikerfirst:
H E R E <-- Make sure to read the ADB Guide.
I recommend doing this with a Mobile just taken out of the box or with any Official ROM of its Service Provider. If you have already Flashed your phone with another ROM but its working fine, then you can use that /efs also.
Why the /efs folder?
This is a very sensitive system folder that contains Phone-specific information such as the IMEI (encrypted in the nv_data.bin), wireless devices MAC addresses, product code (also in the nv_data.bin), and much more. Often users trying to change product codes or trying to unlock the mobile will end up corrupting data in this location.
Why back it up?
Well, let’s resume it saying that backing-up this little folder will keep you away from Samsung service centres.
***WARNING: I take no responsibility to any damage caused by the methods cited and/or written here. Their sole purpose is to back-up data and not to alter in any way the integrity of the original files of the mobile***
What you will need:
* Rooted SGS II to get permissions as a SU (Super User) and perform the backup
* I would suggest learning a little about the terminal commands used (in case you are not familiar with them), as it’s better to know what you are doing rather than typing strings like a little chimp without knowing what they are; if you are a little lazy, then you have a good chance bricking your mobile. <- Busybox Commands(or Google them)
* Terminal Emulator by Jack Palevich (available from the market) <-Terminal Emulator or use ADB which is included in the SDK Development Tools
The standard prompt of terminal (adb) is a $ sign. Once you enter “SU” it will become a # Sign.
***NOTE: Make sure to keep an eye on the screen of your SGS II during this process, because it may request SU permissions [currently doesn't on CF-root]; else, you will get an error (just if it’s the first time). In Terminal Emulator you will need to reset the app after granting permissions cause it usually freezes***
*Remember: to use ADB you need to enable USB DEBUGGING under Applications/Development in your SGS II.
Here are 3 methods, I recommend that you do both Clean and RAW.
Basic, unix permissions lost :
Code:
su
busybox cp -a /efs /sdcard/efs/
Clean :
Code:
su
busybox tar zcvf /sdcard/efs/efs-backup.tar.gz /efs
After this, you will end up with the file efs-backup.tar.gz in your INTERNAL SDCARD in sdcard/efs/, which is a “tarball” or a ZIP of the /efs folder. That file is your backup. You can expand it with Winrar.
You can also back up the mmcblk0p1 (where /efs is stored) under /dev/block which can greatly support in recovering your IMEI in case of a screw-up:
RAW :
Code:
su
cat /dev/block/mmcblk0p1 > /sdcard/efs/efs_dev-block-mmcblk0p1.img
alternative
Code:
dd if=/dev/block/mmcblk0p1 of=/sdcard/efs/efs_dev-block-mmcblk0p1.img
Same thing, the target is the INTERNAL SDCARD in sdcard/efs/, so go ahead and copy the file.
--------------------------------------
original thread by Rawat @ xda: click here

matee89 said:
Without a backup, your IMEI is gone. The only way to get your phone working again is to send it back to Samsung Service.
Click to expand...
Click to collapse
Not 100% true, there are other ways, for example I know how to generate valid nv_data files.
matee89 said:
RAW :
Code:
su
cat /dev/block/mmcblk0p1 > /sdcard/efs/efs_dev-block-mmcblk0p1.img
Same thing, the target is the INTERNAL SDCARD in sdcard/efs/, so go ahead and copy the file.
Click to expand...
Click to collapse
I think using dd is better than cat, I dont know why but I have a feeling cat could do some character conversion in some circumstances, so :-
dd if=/dev/block/mmcblk0p1 of=/sdcard/efs/efs_dev-block-mmcblk0p1.img
or better still do both, cannot have too many backups

Thanks for info Odia! Well, the backup is still important. Saves a lot of time for newbies, so i think that this guide should be sticky. Everyone can see it clearly then

There is already a thread about this...
rawat thread
And there's an app on the way apparently..
app thread

Yes, but this thread is not sticky. If you at least read a little part of mine post you should see that I quoted Hawats thread and put a link to it. My point is that this should be more visible for everyone. To be honest, it should be sticky like the rooting guides and other how to's, because it can give you serious problems with the device when files inside /efs get corrupted. Myself I haven't know about the purpose of /efs since yesterday, because it wasn't clearly mentioned in here. Just want to help other newcomers to Samsung devices.
This app will do exacly the same thing like you will do right now following this guide. It's not released yet, so this guide should be used meanwhile.

matee89 said:
Thanks for info Odia! Well, the backup is still important. Saves a lot of time for newbies, so i think that this guide should be sticky. Everyone can see it clearly then
Click to expand...
Click to collapse
Sure the backup is important, is why I added some input to your thread about using the dd command to make double sure the backup taken was valid.
Can an admin or mod make Rawat's thread sticky pls?

Okay, shall edit and post the alternative backup method with dd comand instead of cat.
Would be great with sticky. I don't think that majority of people who's flashing ROM's know how important this folder is. From what I've heard the nandroid backup in CWM recovery does not backup the /efs so it's needed to be done manually.

before using this comands you should use mkdir /sdcard/efs if you don't want to get an error
I made clean, raw and dd back up. Now I have two files of 20 MB each and one of 28Kb is it ok?

Yes, it seems okay. I saved my efs backup files on my PC as well in case something happens to the internal sdcard storage.

Thank you for that. I will backup mine tonight.

Thank you got the backup with my Note

Re: mp1806
Probably some of the ROMs that you flashed had an automatic backup script included, so you already got a working efs backup on your sd card. If you want to be completly sure if the backup is correct, you can make it manually by following the steps in my first post. Later you can even copy your backup to your PC if you like to.

There is three or four apps by now that aid you in creating EFS backups.
Most have been mentioned in the other (older) EFS backup thread.
It's one app i forgot the name of, EFS-Pro that works from your computer and my own one (see sig).
If you search for "efs backup" on the market you will find "Nitrality" (or however it's spelled, forgot the exact name right now) and my one.
Mine also offers an option to check the EFS backup if it's OK or corrupted, so can be really sure to have a good one when the check succeeds.
Point beeing:
No real need to tinker on the shell anymore

Great Thanks for this

Hi, I am using the RAW method on my Galaxy Note, rooted, but I keep getting a file not found error. Anyone able to help? I got the su and the prompt changed correctly, but after:
cat /dev/block/mmcblk0p1 > /sdcard/efs/efs_dev-block-mmcblk0p1.img
It just says file not found. What am I doing wrong?

Another way is to use ktool made by Hellcat to backup your efs and even restore.
http://forum.xda-developers.com/showthread.php?t=1314719&highlight=ktool
Anyone knows if this tool is as good as command line way?

(nvm)

Odia said:
Not 100% true, there are other ways, for example I know how to generate valid nv_data files.
Click to expand...
Click to collapse
Can you please let me know how to generate it? I HAVE LOST THE EFS FILES ON MY PHONE!

Samsung Tool
Samsung Tool is the easiest and more safe method

how do you restore it?

EFS IMEI Backup?

I have root my S4 and will make a backup from efs/imei but EFS Professional not working with the S4. How can i backup efs?

is it so hard to get a copy of ur EFS folder to safe place ?

You can use TWRP recovery to get a EFS backup
Gesendet von meinem GT-I9505 mit Tapatalk 2

You can back up a whole partition with Terminal Emulator from Play Store.
This is example made for I9505 ONLY!!!!
For I9500 use mmcblk0p3 and efs.img instead!!!
Download it , and run it, then type:
Code:
su
dd if=/dev/block/mmcblk0p10 of=/mnt/sdcard/efs.img.ext4
and it will dump whole partition into one file efs.img.ext4 on your internal SD card
or
Code:
su
dd if=/dev/block/mmcblk0p10 of=/mnt/extSdCard/efs.img.ext4
to save it on external SD.
If something goes wrong and you need to restore it:
Code:
su
dd if=/mnt/sdcard/efs.img.ext4 of=/dev/block/mmcblk0p10
or
Code:
su
dd if=/mnt/extSdCard/efs.img.ext4 of=/dev/block/mmcblk0p10
Keep it safe and enjoy

djembey said:
You can back up a whole partition with Terminal Emulator from Play Store.
Download it , and run it, then type:
Code:
su
dd if=/dev/block/mmcblk0p10 of=/mnt/sdcard/efs.img
and it will dump whole partition into one file efs.img on your internal SD card
or
Code:
su
dd if=/dev/block/mmcblk0p10 of=/mnt/extSdCard/efs.img
to save it on external SD.
If something goes wrong and you need to restore it:
Code:
su
dd if=/mnt/sdcard/efs.img of=/dev/block/mmcblk0p10
or
Code:
su
dd if=/mnt/extSdCard/efs.img of=/dev/block/mmcblk0p10
Keep it safe and enjoy
Click to expand...
Click to collapse
With all respect to your post, I would like to warn people that this is not working for all the models/devices. Although it might look fine when executing the commands, it might not have made a backup of EFS, but of something else... What I know for sure is that it will not work for atleast the international i9505-model of the S4, as the partition layout is different.
In my post below, more details are given on this partition id.
http://forum.xda-developers.com/showthread.php?t=2276599
While executing your commands does not affect the device, it does not always give the people a backup they expect it to be, depending on their device/model. In my case you are able to verify which 'mmcblk' is actually efs on your device. It also gives a TAR backup as option.

Mr_Q said:
With all respect to your post, I would like to warn people that this is not working for all the models/devices. Although it might look fine when executing the commands, it might not have made a backup of EFS, but of something else... What I know for sure is that it will not work for atleast the international i9505-model of the S4, as the partition layout is different.
In my post below, more details are given on this partition id.
http://forum.xda-developers.com/showthread.php?t=2276599
While executing your commands does not affect the device, it does not always give the people a backup they expect it to be, depending on their device/model. In my case you are able to verify which 'mmcblk' is actually efs on your device. It also gives a TAR backup as option.
Click to expand...
Click to collapse
Mate... I've added that it is for I9505!!!!
I9500 have EFS located @ mmcblk0p3...........
thanks

I used GS2 repair from play store. It went through the usual process and I can see the back up file on the sd card. Can anybody more qualified confirm if this app works on S4?
Sent from my GT-I9505 using xda premium

djembey said:
Mate... I've added that it is for I9505!!!!
I9500 have EFS located @ mmcblk0p3...........
thanks
Click to expand...
Click to collapse
Great. You are right, in my case it's mmcblk0p10 as well, as mentioned correctly in my guide already.
Thank you for updating.
HANDSY said:
I used GS2 repair from play store. It went through the usual process and I can see the back up file on the sd card. Can anybody more qualified confirm if this app works on S4?
Sent from my GT-I9505 using xda premium
Click to expand...
Click to collapse
The best thing is to check it with the developer. I do not know what file has been created, although I expect it to be a raw copy using dd. The best thing is to do it manually. Or by the instructions given by djembey, or by the more detailed step-by-step instructions in the thread of my previous post here.

Hey, I managed to backup the EFS folder. Is there any way to modify the backup file and restore it after the modification? I want to change the IMEI number but unfortunately I have no box / cables available to do so. There must be a solution?! I am currently living in Turkey and they restrict western mobile phone usage for foreign people.
thanks a lot
cheers,
ralf

,
ralfa1234 said:
Hey, I managed to backup the EFS folder. Is there any way to modify the backup file and restore it after the modification? I want to change the IMEI number but unfortunately I have no box / cables available to do so. There must be a solution?! I am currently living in Turkey and they restrict western mobile phone usage for foreign people.
thanks a lot
cheers,
ralf
Click to expand...
Click to collapse
Same here with me

i9505 imei null
please can somebody help me,what ever I try not working.Unfortynately everything working,but always show imei null and not have baseband,of course and network too.I am install with Odin few different fabrics roms or how you call that.Last is this one with 4 files inside
I9505XXUGNG8_I9505OXXGNG2_I9505XXUGNG8_HOME.tar.Everything going fine,but havent imei like on start.I am also try few different things with EFS_Professional.but cannot fix my problem.Also I am try to erase EFS,but folder cannot erase,just files inside,and trying other one downloaded from net,but not going.Every time after reboot,EFS be back automatics,Can you help me ,please
If I am write inside EFS folder must be a file nv_data.bin ,I dot have that.Have lots of,but dont see that.I have inside few folders,like imei and etc.. And inside imei folder I have mps_code.dat.I am hope somebody can understand my problem.Can somebody sent to me that file,and can I take from other phone.Is that my solution,or what.HELP PLEASE

this is in function to my i9505,but not help me to solve problem.Somehow I not have file nv_data.bin on my phone in efs folder,and backup and restore not help me.Please do you no some solutions?

Failed EFS restore

Ok, I'm officially in trouble. I have a SM-G900F rooted with towelroot, SuperSu and BusyBox installed. I tried flashing with Mobile Odin Pro the latest NG2 firmware to keep root and not trip Knox. It failed twice (or three times), both times I was able to restore the original firmware with desktop Odin (http://forum.xda-developers.com/galaxy-s5/help/mobile-odin-pro-4-20-issues-t2834671).
Then something strange happened: I noticed that on 4G I had only data but no signal bars (http://forum.xda-developers.com/galaxy-s5/help/help-4g-data-signal-bars-t2837031). Then I had problems connecting to Wifi and a message appeared telling me I am in "Factory Mode" and some things are limited.
It was clear that my EFS partition is corrupted. I installed Root Explorer and there is nothing in my EFS folder (still I can use the phone in 2G/3G/4G for data and 2G/3G for calls but no Wifi).
I have 2 backups for EFS: one is made using Samsung Tools (http://forum.xda-developers.com/galaxy-s3/development/efs-samsung-tool-universal-support-t2602325) and it's an efs.img file, the other is made using some EFS backup tool and it's just a copy of exactly what was in EFS folder (a few folders and files). I tried using Samsung Tools to restore the backup but no luck. When I restart the phone, EFS folder is still empty.
I rebooted in recovery mode and it said "failed to mount /efs". That's probably why Samsung Tools can't do it's job but I'm not sure. At this moment I'm not sure of anything. I think that someone with some knowledge (knowledge that unfortunately I'm missing) can help me fix this.
I really need for some help, so any ideas are welcomed.
Thank's,
Mihai Raducan

..

fffft said:
No TWRP backup, huh? How did I know that was going to be the case? 10 demerits. Okay, you seem to have been on the right track in recognizing that your EFS partition was unmounted and therefore inaccessible in recovery mode.. but you didn't mount it? You didn't give us much detail to work with, but assuming that you have a custom recovery like TWRP, you could go to the advanced /mount menu and check the mount EFS partition. Or if you don't have that option for some reason, mount it yourself e.g.
.
Click to expand...
Click to collapse
It's only stock recovery, no TWRP or CWM.
I didn't mount the EFS partition before because I didn't know how. I'll follow your guide and report back.
Regarding the exact copy of EFS (efs.img): It's done with Samsung Tools but never had a chance to test it, so... I don't know. But let's take it one at a time. First problem: mount efs partition.
PS: My Windows laptop is playing tricks on me so it's going to take a while to reinstall Windows, adb, etc. But I'll be back.
Thank's.

..

Ok, I installed Adb, phone is recognized.
The first line of code
Code:
# ls -al /dev/block/platform/msm_sdcc.1/by-name
gave me a list with the location of efs (and more). EFS is at dev/block/mmcblk0p12.
The second line of code
Code:
# /sbin/mount /dev/block/mmcblk0p12 /efs
gives me : tmp-mksh: /sbin/mount: not found
Am I missing something?

is img of /efs partition enough for restore?
here, it says, that we need to have 3 partitions for full restore..??..: http://forum.xda-developers.com/showthread.php?t=2737448
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
but Samsung tool only makes efs.img..??.. who is right who is wrong?

..

fffft said:
Personally, if an EFS backup program made an image (.img} file and it was the same size as your EFS partition I'm sure that it was an exact copy and try writing it back. It's unlikely to make anything worse. But don't blame me if it somehow goes wrong. I'm just describing an option of last resort and commenting on what I would do with my own phone.
You can check the size of your EFS partition with the cat command (EFS should be partition 12)
Code:
$ su
# cat /proc/partitions
.
Click to expand...
Click to collapse
I checked the size of my efs.img and the size of the partition with the command you gave me. They are both 14MB but on a closer look, adb shows 14336 and Windows reports 14680kb. So I don't know....
fffft said:
You're using ADB instead of a terminal emulator app which is a new variable. There are a lot of ADB variants around and I have no idea what your command interpreter (mksh) or you have done with the shell environment.. which may require syntax adjustments.
Not found implies that the /system partition isn't mounted. But it could also be an ADB syntax quirk, path or symlink error, a typo or.. well, could be a lot of things. Perhaps try the syntax below. Or run the command from a terminal emulator instead of ADB shell.
Code:
$ su
# adb shell mount /system
# adb shell mount /efs
.
Click to expand...
Click to collapse
I installed Android Terminal Emulator and Shell Terminal Emulator (PlayStore) but I got the same thing. What's strange is that in both of them when I run the command "adb devices" they both give me nothing while in adb shell on desktop I get a number (as it should).
I understand that the syntax is for a specific terminal emulator. Tell me please what is that terminal emulator (that you know syntax is correct) so I can try with that one.

..

fffft said:
Try this terminal emulator app.
If you have continued difficulties, you should describe step by step what you are doing. In exhaustive detail or as close as you can get to that. Then someone in the forum will have a good basis to see where you are going astray. Or alternately where I made a typo or whatever the impediment turns out to be.
.
Click to expand...
Click to collapse
This is one the apps I tried with.
I'm describing step by step what I do. What I start with: SM-G900F rooted with towelroot, stock recovery, SuperSU and BusyBox installed, Knox 0x0.
I download and install https://play.google.com/store/apps/details?id=jackpal.androidterm.
Using this app:
Code:
su
and it changes to [email protected]:/#
I enter:
Code:
# ls -al /dev/block/platform/msm_sdcc.1/by-name
and it gives me a list with paths to different things. EFS apears to be at /dev/block/mmcblk0p12
I enter
Code:
# /sbin/mount /dev/block/mmcblk0p12 /efs
and it says: "tmp-mksh: /sbin/mount: not found"
When I try
Code:
adb devices
it gives me no number.
I attached a file where you can see what I did.
One more thing: when I enter (stock) recovery, every time it says "Installing system update" for about 20 seconds and then enters recovery where it says "failed to mount/efs : invalid argument". The CSC part is apparently ok.

..

It doesn't work. From ADB it says "mkdir failed for /efs, File already exists".
And from terminal emulator, (with busybox) it asks for an argument (pic atached).
Is there any way of using Odin to fix this, because it seems that nothing works.

fffft said:
Who is right about what? You didn't give much of a context for your question. The OP said that his EFS was corrupt, so we have been talking about EFS which is self contained in partition 12 or exported as efs.img.
Click to expand...
Click to collapse
i thought there could be more to the problem, not just /efs partition, since he said it was clear to him, and not beeing 100% fact..

..

Thank's for your time. I'm flashing now the original firmware (so I can start fresh) and I'll document every step I take. I'll report back.

Ok, I tried flashing the original firmware (ANE2) and this time I can't even get pass the Samsung authentication screen (the first time you boot your phone and asks for language, Google account, etc), It asks me for the Samsung account and password that this phone was registered with) and it tries for a couple of minutes to verify the credentials (on data network) then it fails saying it is a network error.
I tried wipe cache/factory reset (from recovery) and reinstall a different firmware. Same thing. It seems now it's really messed up.

As mentioned earlier, we did not expect a firmware image to fix your EFS. And the EFS is critical to normal phone operation.
The purpose of stock firmware is so that your phone is stable, reduce variables that might interfere and facilitate fixing your EFS. So I'm not why you apparently expected it to be an outright fix in and of itself?
Having installed the stock firmware should help you achieve your remaining goals. Now you need to decide if you are going to install a custom recovery or not. A custom recovery will increment your Knox flag if it isn't already. That affects very little, but it's your decision. It may affect the private mode feature or warranty claims, however many carriers don't care about Knox and E.U. legislation bars Samsung from invalidating a warranty unless they can demonstrate that root damaged your phone.
Whether or not you install a custom recovery, you will want to try writing your 14 MB EFS backup image to your phone. I believe that you'd find it easier to do so with a custom recovery. But it can be done with a stock one too, you will just have to deal with a bit more syntax in the latter case.
.

fffft said:
As mentioned earlier, we did not expect a firmware image to fix your EFS. And the EFS is critical to normal phone operation.
The purpose of stock firmware is so that your phone is stable, reduce variables that might interfere and facilitate fixing your EFS. So I'm not why you apparently expected it to be an outright fix in and of itself?
Having installed the stock firmware should help you achieve your remaining goals. Now you need to decide if you are going to install a custom recovery or not. A custom recovery will increment your Knox flag if it isn't already. That affects very little, but it's your decision. It may affect the private mode feature or warranty claims, however many carriers don't care about Knox and E.U. legislation bars Samsung from invalidating a warranty unless they can demonstrate that root damaged your phone.
Whether or not you install a custom recovery, you will want to try writing your 14 MB EFS backup image to your phone. I believe that you'd find it easier to do so with a custom recovery. But it can be done with a stock one too, you will just have to deal with a bit more syntax in the latter case.
.
Click to expand...
Click to collapse
I didn't expect to fix the problem, I wanted a fresh start so I can try again the adb/terminal emulator commands. But what I didn't expect was not being able to, basically, start the phone. When you first start a new phone (or after a factory reset) it asks you language, Wifi, Google account and, in my case, for a Samsung account that this phone was paired with.
If I try to connect to a Wifi network the phone reboots itself. If not, it tries via data connection. Google credentials are ok but when it tries to verify Samsung credentials it gets stuck saying that it's a network problem and it doesn't go futher. So I get stuck at this point, between booting and actually being able to use the phone. I can't install anything, I can't receive or make phone calls (like before). I can't go to USB debugging so ADB doesn't see the phone.
I don't want to install a custom recovery because my Knox is 0x0 and my warranty is intact. I live in EU but in this case, it's clear that root access is what got me in trouble and brought the phone in this state. Actually not root access got me in trouble, but what I did with root access

raducanmihai said:
I didn't expect to fix the problem, I wanted a fresh start so I can try again the adb/terminal emulator commands. But what I didn't expect was not being able to, basically, start the phone. When you first start a new phone (or after a factory reset) it asks you language, Wifi, Google account and, in my case, for a Samsung account that this phone was paired with.
If I try to connect to a Wifi network the phone reboots itself. If not, it tries via data connection. Google credentials are ok but when it tries to verify Samsung credentials it gets stuck saying that it's a network problem and it doesn't go futher. So I get stuck at this point, between booting and actually being able to use the phone. I can't install anything, I can't receive or make phone calls (like before). I can't go to USB debugging so ADB doesn't see the phone.
I don't want to install a custom recovery because my Knox is 0x0 and my warranty is intact. I live in EU but in this case, it's clear that root access is what got me in trouble and brought the phone in this state. Actually not root access got me in trouble, but what I did with root access
Click to expand...
Click to collapse
The only way to get your phone to work again and gain access to networks/wifi is by installing a new motherboard if you can`t restore the old EFS folder somehow.
Next time try this method to backup and restore your EFS folder http://forum.xda-developers.com/showthread.php?t=2737448 if you are rooted.

raducanmihai said:
I didn't expect to fix the problem, I wanted a fresh start
Click to expand...
Click to collapse
Sorry that you found it a surprise.. but if reinstalling the stock firmware eliminated your phones problems, that would make it a solution, whereas it's a stepping stone. I did try to explain this earlier, where I told you that installing the firmware would not fix your EFS. And the EFS is essential to normal phone operation.
Regardless of the surprise, you are now on a better footing to finish fixing your phone. But for clarity, your problem started when your EFS got corrupted somehow. And your EFS needs to be restored before the problem will be resolved.
On the positive side, you appear to have a EFS backup, even if the backup app won't easily restore it to you phone. If you stick with it.. you just have some minor hurdles remaining - syntax or whatever - in getting your 14 MB EFS backup restored (written) to your EFS partition.
If you want that done painlessly, then pack a case of beer and your phone into a box and ship it to me. And I'll return it fixed. As it seems unlikely that you'd do that though.. then try to provide as much info as you can here and someone will try to help you finish fixing your phone in this thread.
.

[Q] N910F EFS messed up, lost network access help???

Well, first of all.... I made a clean copy of my EFS folder before having this problem but.....using the lovely and simple commands copy and paste and now the files don't have the correct permissions and owners so nothing changes when I copy them back so my question is...
Could you guys please provide me a list with all the N910F EFS files + permissions and owners?
*EDIT*
My IMEI, serial number, baseband..... are all correct.
Thanks:crying:

Have u tried flashing stock rom through odin.Many users have fixed this problem by using the method
Sent from my SM-N910G using XDA Premium 4 mobile app

RISHI RAJ said:
Have u tried flashing stock rom through odin.Many users have fixed this problem by using the method
Sent from my SM-N910G using XDA Premium 4 mobile app
Click to expand...
Click to collapse
Yes, I tried 3 different stock roms, I also downgraded to stock kitkat and then flashed a stock lollipop rom and... same problem.

ANTONIOPS said:
Yes, I tried 3 different stock roms, I also downgraded to stock kitkat and then flashed a stock lollipop rom and... same problem.
Click to expand...
Click to collapse
same problem here also, except, i have original imei intact and can make calls, send sms etc. flashed original firmware through odin and through kies, no luck, efs file 0mb. I have lost finger print scan and my serial number is wrong.

I had a similar problem a while back, came across this info here, the 'dev' files mentioned are for a N910G, just type 'mount' at a terminal to see which 'dev' file the efs partition mounts on. I used Method 1, but Method 2, does essentially the same thing in the end, so which ever you find easiest. Damn saved my phone, I even bought a replacement online before I found this solutionl.
Fix screwed up EFS Partition.
-------------------------------
posted by Steve Lazarus on XDA Dev on 5th October 2013
http://forum.xda-developers.com/showthread.php?t=2471421
(Used METHOD 2 on 09-01-2015, worked a treat, RaSTuS)
(Will try METHOD 1 next time)
METHOD 1
1. Install stock Firmware via Odin then rerun autoroot (to regain root)
2. Install TWRP via Odin, reboot to recovery.
3. Install SuperSU from external SD Card.
4. Do an "adb shell" when phone is in recovery mode to run commands via TWRP.
From the ADB shell: Reset the EFS partition with the following commands:
mke2fs /dev/block/mmcblk0p13 (for N910G Note 4)
mkdir /efs
mount -t ext4 /dev/block/mmcblk0p13 /efs
Do a factory reset, reboot system
Afterwards, no more boot looping, the phone successfully registered on the
mobile network, and my IMEI is there and correct. Seems like the EFS partition
can rebuild itself now I guess...
Gotta love the XDA community !!!
METHOD 2
You can also try just running Commands via TWRP before using Odin to revert to
stock, re-rooting etc..Worked for me while I was doing some restore testing with
Jovy's modded kernel ..Just trying to save you some time..
Using TWRP Terminal Command To Complete this evolution...
1. Reboot to recovery
2. Hit "Advanced" Select "Terminal Command".
3. Hit "Select" (lower right corner) to select root (/) folder.
4. keyboard will open, type in the following commands, make sure you put the
spaces and / where they need to be, it needs to look exactly as outlined.
mke2fs /dev/block/mmcblk0p13 (for N910G Note 4)
Hit Go - The command will run.
Clear the input box, type the following command:
mkdir /efs
Hit Go - The command will run.
Clear the input box, type the following command:
mount -t ext4 /dev/block/mmcblk0p13 /efs
Hit Go - The command will run.
You can now back out of the terminal command, and follow the rest of the
directions.

rastus.rob said:
I had a similar problem a while back, came across this info here, the 'dev' files mentioned are for a N910G, just type 'mount' at a terminal to see which 'dev' file the efs partition mounts on. I used Method 1, but Method 2, does essentially the same thing in the end, so which ever you find easiest. Damn saved my phone, I even bought a replacement online before I found this solutionl.
Fix screwed up EFS Partition.
-------------------------------
posted by Steve Lazarus on XDA Dev on 5th October 2013
http://forum.xda-developers.com/showthread.php?t=2471421
(Used METHOD 2 on 09-01-2015, worked a treat, RaSTuS)
(Will try METHOD 1 next time)
METHOD 1
1. Install stock Firmware via Odin then rerun autoroot (to regain root)
2. Install TWRP via Odin, reboot to recovery.
3. Install SuperSU from external SD Card.
4. Do an "adb shell" when phone is in recovery mode to run commands via TWRP.
From the ADB shell: Reset the EFS partition with the following commands:
mke2fs /dev/block/mmcblk0p13 (for N910G Note 4)
mkdir /efs
mount -t ext4 /dev/block/mmcblk0p13 /efs
Do a factory reset, reboot system
Afterwards, no more boot looping, the phone successfully registered on the
mobile network, and my IMEI is there and correct. Seems like the EFS partition
can rebuild itself now I guess...
Gotta love the XDA community !!!
METHOD 2
You can also try just running Commands via TWRP before using Odin to revert to
stock, re-rooting etc..Worked for me while I was doing some restore testing with
Jovy's modded kernel ..Just trying to save you some time..
Using TWRP Terminal Command To Complete this evolution...
1. Reboot to recovery
2. Hit "Advanced" Select "Terminal Command".
3. Hit "Select" (lower right corner) to select root (/) folder.
4. keyboard will open, type in the following commands, make sure you put the
spaces and / where they need to be, it needs to look exactly as outlined.
mke2fs /dev/block/mmcblk0p13 (for N910G Note 4)
Hit Go - The command will run.
Clear the input box, type the following command:
mkdir /efs
Hit Go - The command will run.
Clear the input box, type the following command:
mount -t ext4 /dev/block/mmcblk0p13 /efs
Hit Go - The command will run.
You can now back out of the terminal command, and follow the rest of the
directions.
Click to expand...
Click to collapse
I tried that and those solutions didn't work because I'm the biggest idiot in this galaxy:laugh:, some time ago I deleted the EFS golden backup in the service menu and I think that's why it didn't rebuild after I erased the main EFS partition but the good thing is that I made a clean backup of it so I can copy the files back to the EFS folder, the thing is that I just copied and pasted them so now all files have root as the owner and I know some of them had system, radio, wifi... as owners but I can't remember which ones, I think I could fix it if I see a list with the files, permissions and owners. Thanks anyway:good::good:
*EDIT*
Oh!! also I forgot to tell you that my imei, baseband, serial number bla, bla, bla are correct.

please help guys i have same problem but my note is n910f
hello ... its my first comment here ... and i whant to ask ...if i have the same phone ...but ... its a n910f ... its working this metods ? please guys i need help ... thx ...

Hi, I have a N910C and my IMEI got changed when i flashed offical lolipop 5.1.1, and now it wont register on any network, the IMEI isn't fake or corrupted i tried imei analyzer and it says its valid but for a 2005 Phone. I tried deleting /efs entirely/ flash diff firmwares / factory reset / clean kies install, nothing worked. my .nv_data.bak/nv_data.bak is missing. Please help

N910F EFS lost
florinhrib said:
hello ... its my first comment here ... and i whant to ask ...if i have the same phone ...but ... its a n910f ... its working this metods ? please guys i need help ... thx ...
Click to expand...
Click to collapse
i'm new too i'm from Algeria, i have a GN4 with no IMEI, i lost the EFS foldier, the wifi and blueth work but no finger print and no health app, please help

[needed]persist backup of moto g5 plus which is not bricked yet

Hey guys as you know that we are able to get back volte successfully in Moto g5 plus by restoring PERSIST BACKUP.
So I think MAYBE persist partition got corrupted during flashing back stock.
But that backup is from MOTO G4 PLUS ,and some user facing a problem that whenever they reboot volte and imei again gone,and Everytime they have to restore efs (maybe because of that persist partition)so I am requesting you ,can someone please pull out persist backup of STOCK MOTO G5 PLUS WITH WORKING VOLTE (OR G5 PLUS WHICH IS NOT BRICKED YET).
I AM ATTACHING A TWRP FOR TAKING BACKUP WHICH IS MADE BY DEVELOPER.
SO YOU HAVE TO JUST GO IN TO BACKUP AND TAKE BACKUP OF PERSIST PARTITION
You can download twrp from below link.
https://potterroms.ddns.net/TWRP/twrp-3.2.1-1-potter_persist.img
I am not responsible for any brick/damage caused during you taking backu

Alright, so I got a Persist backup using the partition backup & restore app. I don't use VoLTE, but my IMEI hasn't become zero. I'm on Oreo. It's saved as a .img file. If this is helpful I'll upload the file. @akshu2697

thedr34m13 said:
Alright, so I got a Persist backup using the partition backup & restore app. I don't use VoLTE, but my IMEI hasn't become zero. I'm on Oreo. It's saved as a .img file. If this is helpful I'll upload the file. @akshu2697
Click to expand...
Click to collapse
I would definitely love to give it a go. I've had to restore my EFS every reboot since I tried installing Pixel Experience. I'd love to not have to remember anymore!
telegram @bcraw

thedr34m13 said:
Alright, so I got a Persist backup using the partition backup & restore app. I don't use VoLTE, but my IMEI hasn't become zero. I'm on Oreo. It's saved as a .img file. If this is helpful I'll upload the file. @akshu2697
Click to expand...
Click to collapse
Yes,it will be helpful,can you please upload that file.?

akshu2697 said:
Yes,it will be helpful,can you please upload that file.?
Click to expand...
Click to collapse
There you go.

thedr34m13 said:
There you go.
Click to expand...
Click to collapse
i will try ,
thank you so much brother

akshu2697 said:
i will try ,
thank you so much brother
Click to expand...
Click to collapse
No problem. Happy to help. If there's a way to get a better backup, tell me and I'll try.

thedr34m13 said:
No problem. Happy to help. If there's a way to get a better backup, tell me and I'll try.
Click to expand...
Click to collapse
sorry brother ,
i tried your backup,but this backup isn't working,
we need twrp persist backup as i have posted on the thread of volte.

akshu2697 said:
sorry brother ,
i tried your backup,but this backup isn't working,
we need twrp persist backup as i have posted on the thread of volte.
Click to expand...
Click to collapse
Not sure how to backup persist in twrp. Couldn't find instructions anywhere. If you find instructions, tell me and I'll upload the backup.

thedr34m13 said:
Not sure how to backup persist in twrp. Couldn't find instructions anywhere. If you find instructions, tell me and I'll upload the backup.
Click to expand...
Click to collapse
sure,i'll do

DELETED

With a lot of research, I was able to dump the persist partition using adb. My dump will do no good, as I have only been able to get persist back by OP's method. We need someone to dump who has not flashed an oreo rom. Ok, that being said, here is how.
Make sure your phone is rooted.
Make sure usb debugging is enabled.
Boot phone into recovery.
Open adb with phone connected to pc.
Code:
adb devices
You should see your device listed.
Code:
adb shell
You should get ~# and something like a backward arrow [6N. That was mine yours may differ. If you have ~$ instead of ~# you are not rooted properly. If you used magisk you may have to add the sudo module.
Code:
ls -al /dev/block/platform/soc/7824900.sdhci/by-name
This will give you a list of all partitions. Look through them and find one described as persist. Mine was this:
Code:
lrwxrwxrwx 1 root root 21 Jan 1970 persist -> /dev/block/mmcblk0p30
We are interested in the address /dev/block/mmcblk0p30.
We need to type in
Code:
dd if=/yourMountingPoint of=/yourDestination/partitionType
where /yourMounting point is the persist address, if like mine /dev/block/mmcblk0p30. /your destination will be where you want to save it, and partition type should be persist.img.
My command was this
Code:
dd if=/dev/block/mmcblk0p30 of=/external_sd/persist.img
This will give us a proper persist .img file.

Here it is.
I clean flash stock rom (potter_NPNS25.137-93-4) before getting the persist file, was on crDroid 7.1 before. I don't know if volte is working because we don't have it on my country, but I never flashed Oreo before and never lost imei or 4g/lte, so it should be fine.
Hope it helps us and use at your own risk.
https://drive.google.com/drive/folders/1bqdxheka3jKG76AXdEExIdhG81D3agLM

[email protected] said:
With a lot of research, I was able to dump the persist partition using adb. My dump will do no good, as I have only been able to get persist back by OP's method. We need someone to dump who has not flashed an oreo rom. Ok, that being said, here is how.
Make sure your phone is rooted.
Make sure usb debugging is enabled.
Boot phone into recovery.
Open adb with phone connected to pc.
Code:
adb devices
You should see your device listed.
Code:
adb shell
You should get ~# and something like a backward arrow [6N. That was mine yours may differ. If you have ~$ instead of ~# you are not rooted properly. If you used magisk you may have to add the sudo module.
Code:
ls -al /dev/block/platform/soc/7824900.sdhci/by-name
This will give you a list of all partitions. Look through them and find one described as persist. Mine was this:
Code:
lrwxrwxrwx 1 root root 21 Jan 1970 persist -> /dev/block/mmcblk0p30
We are interested in the address /dev/block/mmcblk0p30.
We need to type in
Code:
dd if=/yourMountingPoint of=/yourDestination/partitionType
where /yourMounting point is the persist address, if like mine /dev/block/mmcblk0p30. /your destination will be where you want to save it, and partition type should be persist.img.
My command was this
Code:
dd if=/dev/block/mmcblk0p30 of=/external_sd/persist.img
This will give us a proper persist .img file.
Click to expand...
Click to collapse
How to restore this file brother.?

N1vBruno said:
Here it is.
I clean flash stock rom (potter_NPNS25.137-93-4) before getting the persist file, was on crDroid 7.1 before. I don't know if volte is working because we don't have it on my country, but I never flashed Oreo before and never lost imei or 4g/lte, so it shoud be fine.
Hope it helps us and use at your own risk.
https://drive.google.com/drive/folders/1bqdxheka3jKG76AXdEExIdhG81D3agLM
Click to expand...
Click to collapse
Thank you sooo much brother.
Thank you for your support.

akshu2697 said:
How to restore this file brother.?
Click to expand...
Click to collapse
Aren't you the OP of this? I thought you needed a way to dump the original partitions, and I provided the method with step by step to do so. I've never coded for android systems, but I'm very familiar with close cousin linux, so I suppose I could investigate and learn. However I would think whomever developed the G4 plus method could use the above dump for our phone. I guess I assumed it was you who discovered this method. I'll dig into it further when I get some time, but getting the clean persist dump was what was asked to do.

I was able to write the above persist.img file by:
1. transfer persist.img to my external_sd
2. booting into twrp
3. opening terminal
4. entering
Code:
dd if=/external_sd/persist.img of=/dev/block/mmcblk0p30
However, this placed my EMEI to 0, and I had to restore my saved efs with moto g4 + persist to get signal back. But remember, I had problem with efs every time I reboot, so my case may not be typical of those of you whose moto g4+ persist was working fine for. I would be curious if N1vBruno's persist was at the same address as mine, namely
Code:
/dev/block/mmcblk0p30

Guys who have restored their VoLTE, does your IMEI match the one that came with your phone or has it changed to something else?
I'm just being curious as I thought using someone else's persist backup would restore his IMEI to your phone, or was it efs?
Please correct me if I'm wrong.

psychopac said:
Guys who have restored their VoLTE, does your IMEI match the one that came with your phone or has it changed to something else?
I'm just being curious as I thought using someone else's persist backup would restore his IMEI to your phone, or was it efs?
Please correct me if I'm wrong.
Click to expand...
Click to collapse
It is efs.

[email protected] said:
I would be curious if N1vBruno's persist was at the same address as mine, namely
Code:
/dev/block/mmcblk0p30
Click to expand...
Click to collapse
Yes,
Code:
persist -> /dev/block/mmcblk0p30
psychopac said:
I'm just being curious as I thought using someone else's persist backup would restore his IMEI to your phone, or was it efs?
Click to expand...
Click to collapse
I hope not lol