[Galaxy S III General] aminroslan:
i got the solution sorted out. follow the steps :

THIS IS A MANUAL OF SETTING UP YOUR SIGNALS AND SOLVE THE "NO SERVICE/EMERGENCY CALLS ONLY". DO NOT FOLLOW MY STEPS IF YOU ARE UNSURE. I AM NOT RESPONSIBLE FOR ANY SMARTPHONES BRICKED.

BEFORE FOLLOWING MY STEPS, DO READ & UNDERSTAND THE OP THAT rootSU POSTED.

1. flash stock rom (with baseband emg4 and above so that you'll get efs v2) - my choice of stock rom is bosnia or you can look at sammobile.

2. flash via odin (regardless of any version, i used 1.85)

3. let the phone boot , go through setup, then once youre at the homescreen, your phone signal should be running up now.

(problem solved for stock rom users, check settings>about phone>baseband should be emg4>status>IMEI & SN should be fine)

but if you want to root and get custom rom, boot to download mode and repeat step 2 but flash cf-root and continue the steps.

4. after flashing, let the phone boot up .

5. you should be at the homescreen by now.

(backing up the important datas)

6. download 'root browser' from play store.

7. once downloaded, open root browser>locate efs folder>allow root access>locate for NV_DATA.BIN and NV_DATA.BIN.MD5 .

8. long press NV_DATA.BIN and press copy>click paste in the same folder.

9. it should be shown as NV_DATA - COPY.BIN. repeat step 8 to NV_DATA.BIN.MD5 .

10. once done , in the folder you should have

NV_DATA.BIN

NV_DATA - COPY.BIN

and

NV_DATA.BIN.MD5

NV_DATA - COPY.BIN.MD5

(REMEMBER, THESE FILES ARE COMPULSORY. IF YOU DON'T HAVE THESE 4 FILES, REPEAT MY STEPS UNTIL YOU DO)

11. long press NV_DATA - COPY.BIN > Rename > rename the file to ".NV_DATA.BAK" (DO NOT FORGET THE "." BEFORE "N") > save.

12. long press NV_DATA - COPY.BIN.MD5 > Rename > rename the file to ".NV_DATA.BAK.MD5" (DO NOT FORGET THE "." BEFORE "N") > save.

Congratulations. you have successfully backed up these 2 important files (nv_data.bin & nv_data.bin.md5)

CONTINUE TO NEXT STEP IF YOU HAVE A CUSTOM ROM, BUT NO SERVICE/SIMCARD NOT DETECTED. (Though baseband,IMEI and SN are still intact & correct)

13. flash custom rom (I dont think i need to teach you this lol)

14. Once boot up, go through setup process.

15. You should see that your signal bar is empty , and when you pull down quick settings panel, it says NO SERVICE. under your mobile network panel instead of your service provider.

16. now download root browser (follow step 6 & 7)

17. you should see the files you back up just now in step 8 -12 .

"NV_DATA.BIN

.NV_DATA.BAK

NV_DATA.BIN.MD5

.NV_DATA.BAK.MD5"

18. long press ".NV_DATA.BAK" > copy > paste to same folder > new copy will appear named ".NV_DATA - COPY.BAK"

19. repeat step 18 with ".NV_DATA.BAK.MD5"

20. now you should have a copy of the backups.

.nv_data-copy.bak

.nv_data-copy.bak.md5

21. rename ".nv_data-copy.bak" to "nv_data.bin"

22. click ok > click Overwrite

23. do the same to ".nv_data - copy.bak.md5"

after renaming the ".nv_data - copy.bak.md5" to "nv_data.bin.md5" , it will freeze for about 20s-1min (my experience) , then it will automatically bring you to the homescreen. AT THAT TIME, YOUR SIGNAL BARS SHOULD BE BACK ON ACTION.

so i hope that this post may help some of you to get out from the whole EFS mess.

don't forget to hit Thanks !