If you are reading this, it means that your IMEI and/or EFS folder is corrupted. This can happen when the ROM you are flashing contains an EFS folder and it overrides yours. Or you have ticked Odin’s “Clear EFS Folder” box. Both of which converts your phone to a tablet.
There are multiple guides that involves copying the nv_data.bin file and changing ownership. This post does not cover that procedure, you can read about it here. link
In my situation, a friend has managed to delete the EFS folder on a Samsung Note II LTE, GT N7105. I have found the above method did not work for me. The version of stock that I have restored using Odin is behaving weirdly. It seems that I don’t have write access and yet I could change filenames or delete files. When I attach the phone as a USB, I could not copy files onto it. This reinforce my belief that changing permission of one file is not going to recover my IMEI number.
In the excellent thread by Hopper8 in XDA (link) on recovering from a failed Odin flash, he mentioned a 3 part stock flash recovery method. Instead of the usual one file, there are three separate files to flash. PDA, Phone and CSC. Image below shows Odin flashing a PDA file. Phone is BL.
After a few frustrating attempts to download the required files, I still got nowhere. Either the hosting service has been discontinued (hotfile), no file found or throttling was so severe, I downloaded only 50MB of 1.2 GB.
Back to the drawing board. This time round I tried to use Kies to connect to the phone. Both Kies 2 and Kies 3 refuse to recognize the phone. Googled some more and someone suggested using the emergency recovery in Kies. (link) Kies 2 needs to download some components before upgrading, whereas Kies 3 starts immediately. It helps if your device can be upgraded to Android 4.3 I decided to use Kies 3.
So here it is the simplest and easiest way to recover your EFS Folder.
- Fast and stable (~ 2 hours) Internet connection
- Kies 3 (link)
- Back up of all content, SMS, playlist, music, S Notes etc.
- Device minimum charge 70%
- Launch Kies 3
- Click on “Firmware upgrade and initialization”
- Enter exact model number exactly as in the label in Battery compartment
- Enter serial number exactly as in the label in Battery compartment
- A menu will pop up asking to switch phone to “download” or “recovery mode”
- Check “I have done this”, select “No backup”
- Click “Start Upgrade”
- In the window “Unsupported device alert”, do not click “Confirm” device. Just ignore but do not close the window.
- Kies will start downloading a recovery image for your device. It is about 1.2 GB. This will take about 30 mins to 1 hour. Do not touch the computer, go do something else.
- Once downloaded, Kies will decrypt and expand the files.
- Followed by automated flashing.
- The device will reboot to complete the process. Do not click any of the Kies window.
- Open Windows Explorer, go to %temp%, look for the most recent folder. The Samsung Stock firmware files will be in there. Copy the whole folder and archive.
- Exit from Kies.
Using the phone app, type in *#06# to verify your IMEI number.
There you have it the easiest method to recover the EFS folder and IMEI. Now all that is done, time for to back it up. Here are some apps to backup and restore EFS folder. (link)
Update 2 Apr 14
It may be possible to do this even faster. Note you need to have Android installed. I think it is independent of version and type. (link) Sorry, I don’t own this video and it was taken private by the owner.
Update 3 Jun 15
Try this 3 minute method. This works even you have flashed other ROMs. This method is only useful if you have a working OS, but no IMEI. If you have none, you may be better off using the Kies method.