User input unlock code Samsung S4 GT-I9500b
Enter unlock/defreeze code in Samsung S4 GT-I9500b, if the "wrong code"
If you unlock a mobile phone Samsung S4 GT-I9500b or model you have difficulty with putting unlock code, this instruction should help you.
- Make sure that you are properly and accurately pointed IMEI number. You can do this by dialing * # 06 #;
- Dial the combination * # 0011 #;
- Press the MENU button and from the menu, press BACK. Nothing should happen - go to the next step;
- Once again, press MENU, to return to the input panel;
- In the box that appears, enter 1 and press OK;
- Wait for access to the service menu;
- Press  Display Settings>  Phone management>  Network lock. Then you will see 3 options lock;
- Press  Perso Sha256 INFO. The screen should change slightly;
- Press MENU, and then, when the menu appears, gently press BACK to return to the previous screen;
- Press  Perso Sha256 ON. The screen should change again to a one-line message.
- ENABLED_FLAG  restart Samsung, hold the power button and press the reset button;
- Thereafter, a request code, enter the unlock code received Samsung.
WARNING! If you see two lines that cannot be changed, you must do the following:
- Press MENU, to go back and select  Perso Sha256 OFF;
- Emerged from two lines, select the first! You should get a message MENU NOT EXIST;
- Press MENU, to go back;
- Press  Perso Sha256 OFF (make sure that the row is selected );
- Go back to back;
- Press  PERSO SHA256 ON (make sure that the row is selected ).
A few more tips on this issue:
If the correct unlock code, some models of Samsung displays a message that the code is invalid. In this case, enter the unlock code (NCK or Network) and click Done/OK/OK. After that, enter the code again and Freeze unlock code. Pre BACKUP and do HARD RESET (Settings> Privacy> Factory data reset> Reset phone> Erase all). Specify whether the phone sews and/or modify any ROM (in these cases, even the correct code will not work).
Some models may have a specific (other) sequence.
The most common problem encountered with Samsung S4 Europe based on Jelly Bean. To solve them, remove the firmware, install the original and try again to make DEFREZE. Record version 4.2.1, although 4.2.2 should not cause any problems.
Order Samsung unlock you can following links:
Discuss unlock Samsung forum you can follow the link.