[WARNING!] Backup your /efs folder before you flash

teo74 · Oct 29, 2010

***Please backup your /efs folder with Root Explorer or similar before you flash any ROM!***

Here is what happened to me:
a) I flashed some firmware which changed my phone's product code.
b) I tried to restore it by editing the nv_data.bin file contained in the /efs folder.
c) This made my phone show a corrupted IMEI (004999010640000).
c) A corrupted IMEI means lots of trouble, in my case I cannot download apps from market anymore
d) If you don't have a /efs backup your only chance is sending your phone to Samsung for repair (it's illegal to modify IMEI and moderators will ban you for discussing this subject in their forum).

The /efs folder is located in the root of you phone, it is only visible with Root Esplorer or similar, and contains IMEI and product code information which is signed and matching, don't change its contents unless you have a HEX editor (I wrongly used wordpad instead).

If mods think this warning will save some headaches to forum users, they could sticky it.
Probably it will help reduce IMEI modification discussion as well!

tb5... · Oct 29, 2010

imma do this now just incase...

took one for the team huh... good looks...

EarlZ · Oct 29, 2010

I understand that modifying your IMEI is illegal here but there should be considerations on how to restore the IMEI back to original state if it was damaged by a firmware flash and no usable nv_data backup, the information on the nv_data is encrypted and from what I understand the IMEI data on nv_data has to match the hardcoded IMEI so Im not sure if its possible to change the IMEI on the SGS by just changing the nv_data contents.

dupel · Oct 29, 2010

Wow, thats a

this was discussed to death a few month ago and only firmware to do so is JPC, which no one would flash now.

And you shouldn't toch those files, as they are signed (you have to delete so they are recreated from back up). Go and search a bit (look for specific topic and topics with "Release" in them).

EarlZ · Oct 29, 2010

I was able to flash JPC ages ago even before the warning on the efs came out, there was a guide on how to restore the IMEI from the back up.. sadly on my end the back up was also corrupted, Not much of a big deal for me as in my place IMEI duplicates dont really matter.

iynfynity · Nov 1, 2010

guys i have unlocked my samsung vibrant to other carriers, all is going good. then i accidentally deleted my new efs folder. when i copied my old efs (from the locked phone) my IMEI was screwed up. but still my phone is working fine all that is not good is my IMEI is changed to a different number which has a lot of zeros.

how can i fix this problem?

Shivatink · Nov 1, 2010

i got a backup of my efs folder but do anyone knows how to restore it back

sztupy · Nov 1, 2010

dupel said:
this was discussed to death a few month ago and only firmware to do so is JPC, which no one would flash now.

But it's always safer to keep a backup of that folder. Any malicious code can delete/modify the ocntents of that folder (with su permissions), and you can't get it back completely by flashing, only by backup.

skyworxx · Nov 1, 2010

I backed up my folder and hopefully i'll never need it, but how would I restore it in the case my imei is broken?

omnia-one4all · Nov 1, 2010

how to

Probably a noob Q but how do you backup nv ? Tried kalpik's command line but seems that it doesn't work on jpa

Fr4gg0r · Nov 1, 2010

teo74 said:
***Please backup your /efs folder with Root Explorer or similar before you flash any ROM!***

Here is what happened to me:
a) I flashed some firmware which changed my phone's product code.
b) I tried to restore it by editing the nv_data.bin file contained in the /efs folder.
c) This made my phone show a corrupted IMEI (004999010640000).
c) A corrupted IMEI means lots of trouble, in my case I cannot download apps from market anymore
d) If you don't have a /efs backup your only chance is sending your phone to Samsung for repair (it's illegal to modify IMEI and moderators will ban you for discussing this subject in their forum).

The /efs folder is located in the root of you phone, it is only visible with Root Esplorer or similar, and contains IMEI and product code information which is signed and matching, don't change its contents unless you have a HEX editor (I wrongly used wordpad instead).

If mods think this warning will save some headaches to forum users, they could sticky it.
Probably it will help reduce IMEI modification discussion as well!

That's why I don't care my productcode. I think it changed to KOR long time ago.

androidfreak2010 · Nov 1, 2010

I already have JPO. should I still backup efs for later flashes or did i have to do this on eclair? My IMEI is still OK. Never had JPC though

ragin · Nov 1, 2010

androidfreak2010 said:
I already have JPO. should I still backup efs for later flashes or did i have to do this on eclair? My IMEI is still OK. Never had JPC though

Some people say that JPA is ok, BUT JPO corrupted their IMEI. Its what was said.

teo74 · Nov 2, 2010

I am sorry that my post annoyed some senior members whose opinion I respect and to whom I am thankful for their job here on XDA.
I only own an Android phone since a month and previously I only visited WM 6.5 forums, so I missed all the discussions about this subject.
That's why I thought it would be a good idea to have a warning stickied somewhere for total noobs like me.

For those needing a way to restore their backups it depends on what they did to save their data:
-if they have copied the /efs folder with root explorer or cp command just copy them back to your phone's /efs folder.
-if they have a efs-backup.tar.gz file in their internal memory they have to type in ADB or terminal emulator the command:
su
busybox tar -xvvzf /sdcard/efs-backup.tar.gz

Pegart · Nov 18, 2010

I just checked the esf folder on my pohne with astro file manager and it's empty. What's with that?

teo74 · Nov 18, 2010

Astro is no good for that, you shoul use root explorer or similar.
If your IMEI is ok you definitely have a good /efs folder content.
Search forums for ways to backup its files (either use root explorer or adb or terminal emulator).

Sent from my GT-I9000 running Doc Froyo v7.6.2 JPO

Slowp0ke · Nov 18, 2010

I think I deserved that, that's why I have switched to a new account on xda.

Sent from my GT-I9000 running Doc Froyo v7.6.2 JPO

euclides5370 · Nov 2, 2011

i move my efs folder to sd card and i moved back do root and now i dont have emei number anymore me cell is infuse 4g whats can i do or its gone...

kuhne · Dec 17, 2011

So, just to make sure.. I opened Root Explorer on my galaxy s2 (with villain rom 3.0) and copied the EFS folder and transfered it to my sdcard, then I also copied it from my sdcard and stored it into a backup folder in my computer.

Does this mean that if my phone somehow becomes corrupt and i lose my IMEI and what not, I can just restore that efs folder with the one I just backed up and my phone will work again?

$omator · Dec 17, 2011

yes backup - if fail - restore

[WARNING!] Backup your /efs folder before you flash

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