[GUIDE] Fix IMEI Null and Baseban Unknown!! on Galaxy S advance
In some specific firmware regions when we move to custom roms or another regions rom we get this error imei null and baseband unknown. Here is the way to fix this problem
1.First you should install stock rom of your region so that you get your imei and baseband back.
2.After this install root explorer or any another root browsing apps and navigate to /system/lib and search a folder called (tee) inside there and copy that (tee) folder to your external sd card or a pc.
3.If you want to flash custom roms then open your custom rom using 7-zip and navigate to /system/lib and drag and drop your original (tee) folder there and replace with custom roms (tee) folder.
4.After that you can normal flash that custom rom and your imei null and unknown baseband will be solved.
5.Another method is if you move to another region firmware then after installing firmware manually delete (tee) folder from /system/lib and put the one you backed up in /system/lib and fix the permissions to rwxr-xr-x and reboot your system.
6.All done enjoy...
This works for both gingerbread and jellybean roms