I installed CyanogenMod 10 Nightlies on my Galaxy S1, coming from CyanogenMod 9.
On every reboot I get the message:

Warning! A problem was detected with your device. Your device IMEI number is invalid. And invalid IMEI number could cause network issues including the inability to call emergency numbers.

Sometimes I have network issues and my handy just won't connect to the Internet(even though it shows E/H Connection)

I once made a backup of my /efs/ partition, I already restored it but the message still appears.

3 Answers 3



Warning message

The CyanogenMod 10 is the first update with the code to detect an invalid IMEI.
You could already have an invalid IMEI and don't know about it.

The issue with an invalid IMEI is that you may have emergency calling problems (inability to do emergency calls).

Confirm IMEI

Does the IMEI reported match the number under your battery?

Dial *#06# and the IMEI will be presented on your screen.

Possible Solution

From this code.google.com thread, the user at comment 5 managed to solve the issue:

Steps I took to solve the problem:

  1. Flash my phone by Odin to version 2.2.1
  2. Update to CM9 using Recovery with stabile version od CM9 http://download.cyanogenmod.com/get/jenkins/5805/cm-9.0.0-galaxysmtd.zip
  3. Update to CM10 using last version of kernel.
    I used cm-10-20120822-NIGHTLY-galaxysmtd.

Between steps I did wipe data/factory reset and wipe cache partition. Now my IMEI is correct.

After cleaning the phone and updates do CM10 I recommend installing gapps-jb-20120726-signed, because your phone will be clean as a baby after birth.

  • Okay, i just checked it my IMEI is invalid, now I would be intrested in a solutions apart from Reinstalling/Flashing. Another question comes up why are calls and (sometimes) Internet without a valid IMEI? I always thought it would be necessesary. Thanks for your very informative Answer!
    – theodm
    Commented Sep 8, 2012 at 13:05
  • Short research reveals, i'm not the only one affected (forum.xda-developers.com/showthread.php?t=842775) [I have the same IMEI].
    – theodm
    Commented Sep 8, 2012 at 13:10
  • 1
    @wayback Do you have a backup of the efs folder which contained IMEI? If you have, you can restore it and fix the issue..
    – Zuul
    Commented Sep 8, 2012 at 13:21
  • I only had the one I already applied :/
    – theodm
    Commented Sep 8, 2012 at 13:21
  • 1
    @imz--IvanZakharyaschev I have not used Heimdal, but by the information about it, you should have no problems..
    – Zuul
    Commented May 20, 2013 at 9:25

This is usually caused by a wrong/corrupted/replaced /efs/nv_data.bin.

If you have a backup of /efs

It is likely, that some ROM installer created one for you.

If you have a backup of the /efs folder on your SD-Card then it's safe to simply copy the files from the backup to /efs:

adb shell              # open a shell
su                     # become root
cd /sdcard/backup/efs  # change directory to the backup
cp -r * /efs           # copy the backup to /efs 

This should restore your IMEI back to the factory value.

If you don't have a backup of /efs

Then you have to go with Zuul's answer.


Just flash your device with official firmware. It may be a problem with the CyanogenMod 10 nightly builds, not your device.

  • 1
    But these nightlies are also working for other people.
    – theodm
    Commented Sep 8, 2012 at 11:46

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