Galaxy S3 Backup And Restore Imei Without Root.

INSTRUCTIONS:

1) Download NV reader/writer HERE and install THESE drivers.

2) Dial *#7284# and select "Qualcomm USB Settings" then check "RMNET + DM + MODEM".

*If you are running a aosp rom (cm9,cm10,aokp etc) you can use the diag method described HERE

3) Save item 00550 with NV reader/writer. You can write the backup directly back to the phone. This backs up your IMEI only.

*If you want a FULL NV backup read the phone with the default values [Range (Dec): 00000-65535].

4) Dial *#7284# and select "Qualcomm USB Settings" then check "MTP + ADB".

Demonstration video HERE

IMEI ALREADY CORRUPT?

1) make a backup of item 00550 like described above and open with your favorite text editor.

2) Separate your IMEI (find it behind the battery) into blocks of two but with the first digit alone, like this-

353022050234285
=
3 53 02 20 50 23 42 85

3) Now add an "A" after the first digit then reverse the two numbers in all the other blocks, then add a 08 to the beginning. Like this-

3 53 02 20 50 23 42 85
=
08 3A 35 20 02 05 32 24 58

4) Now replace the first nine values in the NV block with your converted IMEI and save the text document.

5) Write the NV back to the phone and then reboot.