Sometimes bad things happen and you don’t even know it. Flashing modules can wreck your WiFi, kernels can bork your camera and, and flashing some ROMs can mess with your EFS folder—and thus your IMEI—on Samsung devices including the popular Galaxy S II I9100.
XDA Forum Member vaskodogamagmail has posted about a method that may help users restore their IMEI if the all-important EFS folder is modified by accident. In a nut shell, restoring your backed up IMEI involves deleting the corrupted EFS folder, creating a new one, and doing a few file modifications with a root-enabled file explorer. In the words of the developer:
so I researched. searched all the forums and didn’t find anything that could cure my phone’s IMEI and set it to the original IMEI number. so I experimented and after some hours, I fixed my IMEI.
one thing that led me to the conclusion that ” .nv_data ” file is the thing that I need to fix the IMEI is that they share a very look alike name, and they have the same 2MB size.
While the guide was written with the Galaxy S II in mind, the method should work on all Samsung devices with EFS folders. Those looking to restore their IMEI should visit the original thread for additional information and the full method. Just be sure to back up your device, including the contents of your EFS folder, before getting started._________