[Q]How do we backup our efs ? - Galaxy S III Q&A, Help & Troubleshooting

This is important I think we should figure out a way asap
Sent from my GT-I9305 using xda app-developers app

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install android terminal to your device
and try the command below
Code:
su
dd if=/dev/block/mmcblk0p3 of=/mnt/extSdCard/efs.img

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Great I did it now I have efs.img which is 20mb is this my backup ? Jus curios how come with k-tool and i9300 it saves 2 files and much smaller. What's the difference
Sent from my GT-I9305 using xda app-developers app

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compression level... if u wan a smaller file , u can download kzn or my rom and u can just backup efs with it without flashing rom..

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nah 20 mb is fine thanks dude, I am just wondering why there was 2 files with the K-tool but one with this way

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I am out of thanks I have been thanking the I9305 Devs all day, Dont worry another load coming your ways tomo lool

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nv_data.bin not in efs folder
Hi guys,
I used Total Commander to copy my /efs directory to a backup folder within the internal sd card, so it is likely that all file permissions are retained in the efs backup. However, I did notice that my /efs directory did not contain nv_data.bin, even though my IMEI is intact. Can anyone also check whether you have nv_data.bin inside your /efs please?

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No i dont have that file in that directory......Prodigiez way is excellent a nice neat Img file has been created with all the efs valuable info/data..... My Rom Is now De-Bloated, Zip_aigned/Deodexed, Rooted, Unbranded and Nandroided thanks to all these devs and my motivation

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My god what rock have you lot been living under for the last year or so?
Download the POPULAR and VERY WELL KNOWN EFS Pro application from my sig.
Sent from my GT-I9305 using Tapatalk 2

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there you have it, I have used your windows tool and it created the exact same EFS.img as does this command line
Code:
su
dd if=/dev/block/mmcblk0p3 of=/mnt/extSdCard/efs.img
But your software way is much easier and even has a way to restore it. thank you very much yeh i must of been living under a rock cause all i ever knew about was K-tool with my previous phone i9300, but K-tool does not work with the I9305

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Moving to Q&A

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Maybe its just me but I prefer the old style copy and paste method. Using root explorer or similar I simply copy the efs and factory folders and save in multiple places (external sd, PC etc).
Sent from my GT-I9300 using xda premium

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sxi200 said:
Maybe its just me but I prefer the old style copy and paste method. Using root explorer or similar I simply copy the efs and factory folders and save in multiple places (external sd, PC etc).
Sent from my GT-I9300 using xda premium
Click to expand...
Click to collapse
Not a good idea as you're also losing the permission bits (I take it your external SD is a variety of the FAT file system and your PC NTFS). For example, nv_data.bin has a mode of 0700 and is owned by radio:radio. Say your /efs folder gets wiped and you then copy back your efs folder from your backup. The file (since the umask seems to be 077) will now have the mode as 0600 and be owned by root (because you'd be using Root Explorer/Terminal Emulator to copy back the files which runs as root and not radio). Whatever process (presumably running under the user radio) that looks at that file now may not be able to do so now it's owned by root.
With a tar backup, you're still preserving the permissions which are just as important as the files themselves (though you could look at another GS3 to figure out the correct permissions, granted). With a backup to an image using dd, well, it's the raw partition so I imagine everything on /efs gets backed up.

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qwerty12 said:
Not a good idea as you're also losing the permission bits (I take it your external SD is a variety of the FAT file system and your PC NTFS). For example, nv_data.bin has a mode of 0700 and is owned by radio:radio. Say your /efs folder gets wiped and you then copy back your efs folder from your backup. The file (since the umask seems to be 077) will now have the mode as 0600 and be owned by root (because you'd be using Root Explorer/Terminal Emulator to copy back the files which runs as root and not radio). Whatever process (presumably running under the user radio) that looks at that file now may not be able to do so now it's owned by root.
With a tar backup, you're still preserving the permissions which are just as important as the files themselves. With a backup to an image using dd, well, it's the raw partition so I imagine everything on /efs gets backed up.
Click to expand...
Click to collapse
Thanks for that useful post, answered a couple of queries I had :thumbup:

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qwerty12 said:
Not a good idea as you're also losing the permission bits (I take it your external SD is a variety of the FAT file system and your PC NTFS). For example, nv_data.bin has a mode of 0700 and is owned by radio:radio. Say your /efs folder gets wiped and you then copy back your efs folder from your backup. The file (since the umask seems to be 077) will now have the mode as 0600 and be owned by root (because you'd be using Root Explorer/Terminal Emulator to copy back the files which runs as root and not radio). Whatever process (presumably running under the user radio) that looks at that file now may not be able to do so now it's owned by root.
With a tar backup, you're still preserving the permissions which are just as important as the files themselves (though you could look at another GS3 to figure out the correct permissions, granted). With a backup to an image using dd, well, it's the raw partition so I imagine everything on /efs gets backed up.
Click to expand...
Click to collapse
I've used the copy / paste method on S1, S2 and S3 and copying the folders / files back manually with root explorer works all the time. Haven't had any issues with permissions.
I test by purposely corrupting my imei (yes I'm crazy) and copying the backup back and all is good. Mind you I also have the auto generated tar backup as well but still prefer the copy / paste method.
Sent from my GT-I9300 using xda premium

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Fair enough, I'd just rather restore from a tar backup since I believe there's a reason why nv_data.bin for example is owned by radio, but good to know it works.
Sent from my GT-I9300 using Tapatalk 2

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qwerty12 said:
Fair enough, I'd just rather restore from a tar backup since I believe there's a reason why nv_data.bin for example is owned by radio, but good to know it works.
Sent from my GT-I9300 using Tapatalk 2
Click to expand...
Click to collapse
Well I just checked 2 phones:
S1: I have previously restored the efs folder via copy / paste and the current owner is 'system'.
S3: It's my second S3. Unlike my first unit I haven't repasted the efs folder. Owner is 'radio'.
Conclusion is that you are correct about permissions not copying over correctly with the copy / paste method. It's an easy fix via root explorer to change if required, but not ideal especially for noobs.
Fortunately the change in owner didn't cause any issues but still probably best to use the tar method as you suggest just in case.
Thanks for the info.
Sent from my GT-I9300 using xda premium

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Read this....very useful
http://forum.xda-developers.com/showthread.php?p=30682712

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btemtd said:
This is important I think we should figure out a way asap
Sent from my GT-I9305 using xda app-developers app
Click to expand...
Click to collapse
Well, obviously, you copy the contents of the efs partition
Code:
/efs
and zip it into a tar ball.
Then you put it safely onto your dropbox and voilà.
Hope I could help!
LG familyguy59/Beatsleigher

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does nandroid backup saves EFS as well?
in my backup folder I have these two files:
efsbackup.tar.gz
efsdev-mmcblk0p3.img.gz
but I dont remember backing them up