Cho hỏi về iphone4 unlocked?

Mình có mua code unlocked ở SwiftUnlocks cho iphone4 của mình và có nhận được mail trả lời.
Lần đầu;

here is your unlock code for AT&T IPHONE EXPRESS (1-24 HOURS) IMEI 012426002494667.
UNLOCKED
Visit our how to pages to read upon how to unlock your cell phone.
http://www.swiftunlocks.com/how-to-unlock-cellphone
Regards,
SwiftUnlocksth

Và lần thú 2;
This phone shows unlocked.

Make sure the Iphone is updated to the current 6.1 or latest version
for your model
Make sure ITUNES is updated to the 11.0.1
Make sure the phone is not jailbroken. You will have teo remove the
jailbreak (lower baseband). You can google/youtube how to do this.

Also try doing this process again on another computer. Also if the
phone is reported STOLEN/LOST it will not work on USA GSM. It will
only work overseas. The phone will not work on
Sprint/Verizon/Net10/Straighttalk

Also if the phone is NOT ACTIVATED, it will not work. You will need to
activate it by using an ACTIVE AT&T USA sim card

To complete the unlock, simply:


1. Make sure you have the latest version of iTunes installed.
Make sure an sim card is inserted in phone.

2. Open iTunes on your MAC or PC and verify that you have
Internet connectivity.

3. Connect your iPhone to iTunes by USB cable.

4. Back up your iPhone. How to back up: http://support.apple.com/kb/HT1766

5. Complete the setup assistant and restore your backup

6. After the process has finished, disconnect your iPhone, wait
10 seconds, reconnect to iTunes. It’s fully unlocked.

Mình khộng hiểu lám men mới mà, máy mình là iphone4 dùng gevay sim và đã jailbreak mong các ban cho ý kiến nhụ vậy máy mình có unlocked đuọc khộng? và chỉ mình cách unlocked với mình sợ máy thành cục gạch lám. Cám ợn mọi nguòi nhiều