http://forum.xda-developers.com/show....php?t=1093476 and I've given credit.
--------------HOW TO UNLOCK SAMSUNG 4G i997---------------------
Hello, I will give you step by step instructions on how to unlock your Samsung Infuse 4G or Samsung i997 so you can use it on T-Mobile. I will give full credit to sanfranx415 from xda forums but I wanted to do things a little different and I want to make the process a little more user friendly and less technical. We all get there eventually and I want to be has helpful as possible.
Step 1) Remember, your phone must be rooted. If your phone is already rooted and has a program called Superuser in the menu then slip Step 1. If not, here's a link http://www.addictivetips.com/mobile/...superoneclick/ and if it ever goes down remember the program is called Superoneclick. Google it, download it and make sure your phone is in usb debugging mode, connect it to your computer while superoneclick is open and click root. It's that simple
Step 2) On your computer (not the phone), install a program called "010 Hex editor". Don't have to register Link is http://www.sweetscape.com/download/d...010editor.html . Remember you're installing this on your computer, not phone.
Step 3) On your phone go to the market and install terminal emulator https://market.android.com/details?i...roidterm&hl=en . If the link changes just search for Terminal Emulator in Google. Remember you're installing this on your phone, not computer. Remember root must be installed, REMEMBER STEP 1?, for this program to work.
Step 4) On your phone, open up terminal emulator and you will see a blue screen. Don't be scared. I want you to correctly type the following EXACTLY...
TYPE THE FOLLOWING:
(then press enter)
TYPE THE FOLLOWING:
(then press enter, now your phone might ask for superuser permission, ALLOW it or say YES. You may not have to do this step, if it asked you before)
Now you will do one of the following below. Pay attention.
IF YOU HAVE AN EXTERNAL SD CARD TYPE THE FOLLOWING:
dd if=/dev/block/bml3 of=/sdcard/external_sd/bml3.bak
(then press enter)
IF YOU DON'T HAVE AN EXTERNAL SD CARD TYPE THE FOLLOWING:
dd if=/dev/block/bml3 of=/sdcard/bml3.bak
(then press enter)
Step 5) Now, find the file on your External SD card or Internal Storage depending on your situation and transfer it to your computer. If you don't know how to find the file. Plug your phone up and enable Mass Storage or Connect USB Storage. I won't baby you on how to find it. It should be somewhere on your phone or external SD card if you did step 4 correctly. Transfer that bml3.bak file to your computer. I recommend the desktop so will always know where it's at. You can delete it later if you want. So transfer it to somewhere on your computer.
Step 6) On your computer, open up 010 Hex Editor
Step 7) IMPORTANT: In 010 Hex Editor go to the Menus at the top and select VIEW then LINEFEEDS then SELECT CUSTOM, now SET YOUR BYTES TO "32" Nothing Less. If you don't do this, you won't find your unlock code. Do it.
Step 8) While you're in 010 Hex Editor, click Open and locate the bml3.bak file you created and open it. There will be a bunch of letters, numbers or whatever, ignore them for now.
(CREDIT TO FR0Z3N FOR CLARIFYING THE FOLLOWING 2 STEPS)
Step 9) Now press CTRL+F on your keyboard to search for a hex string. Now a box that says Find should pop up and when the search window pops up select "Hex bytes (h)" in the Type field by pushing the down arrow and then search for the following string below:
"FFFFFFFFFF0100000000" ALL TOGETHER WITH NO SPACES, Then Hit the FIND ALL button to the right, some of you will get many results and others up to 10 results on your screen below (not mine, someone else's computer)
Step 10) Now, if you look at your Hex editor there are 3 window panes on the selected line (See Image Below, my computer). IMPORTANT: scroll to the right using the scroll bar that's in the bottom, middle of the screen. You should see three windows panes.
Step 11) This is where a lot of people are getting confused. So pay attention. Now, Do you see where it says Address Size and Value? Click the text or results under it and ABSOLUTELY MAKE SURE your scroll bar right above it is all the way to the right. It's important because when you click it your computer will try to bring the scroll bar to the left. So click it, and scroll to the right.
Step 12) Go through each result from the above search and you will see on the 3rd window pane (as shown on pic above) after the hex keys there is an 8 DIGIT CODE (Write this code Down) this is your unlock code NCK for your phone. Write it down somewhere NOW!!
Sidenote from Sanfranx415: SCAN THROUGH EACH RESULT AND YOU WILL SEE THAT IN YOUR RESULTS SOME OF YOU MAY GET UP TO 3 DIFFERENT 8 DIGIT CODES WRITE THEM ALL DOWN NORMALLY THE 8 DIGIT CODE THAT APPEARS THE MOST WILL BE THE ONE THAT UNLOCKS YOUR PHONE THE OTHER CODES MAY BE YOUR FREEZE CODE BUT I HAVE NOT TESTED THIS YET THIS 8 DIG CODE SHOULD SHOW ON AT-LEAST ONE MORE RESULT CHECK ALL YOUR RESULTS FROM THE SEARCH ABOVE( SOME OF YOU WILL HAVE YOUR CODE SHOWN AT-LEAST 2 TIMES AND SOME OF YOU WILL HAVE THE CODE SHOW MORE THAN 4 TIMES) YOUR RESULTS MAY VARY EVEN UP TO 39 RESULTS AGAIN SCAN THROUGH ALL RESULTS
Step 13) Okay, welcome back. Now I recommend that you take out your AT&T sim or whatever sim is in there, THEN turn off your phone. Insert the T-Mobile or other carrier sim card
Step 14) Turn on the phone and when you do you'll be prompted to enter a Network Unlock Control Key. Use the code that you received in step 12. You should have written it down somewhere like I instructed you.
Step 15) After you enter your NCK or Network Unlock Control Key hit Unlock, Yes, Go or whatever it says to proceed and it should say "network unlock successful"
VIOLA!!! Your Samsung Infuse 4G is now unlocked from AT&T.
Credit to: http://forum.xda-developers.com/show....php?t=1093476