Ok few things you will need
1. cdma workshop newest verison demo
2. DFS free
3. Need to install get my msl from app store
4. drivers for your S3 just plug your phone in to pc and thats the drivers u need
5. Need a clean esn for boost i used the old samsung prevail wifes old phone but i changed the numbers will show u that later
I did this on windows vista
Step 1
run "get my msl" get your msl code. If it does not work just dial ##3282# hit edit even if u dont have the code just enter 6 random numbers then hit ok then go to the get my msl and run it should give u the code now.
Step 2
Dial ##diag# (##3424#)
choose cdma
Plug s3 in to pc
Then go to cdma workshop in the upper left hand u will see ports click it then select samsung serial port NOT virtual port then on cdma click connect then go to security tap you will see 4 options go to passwords and choose samsung default then send will see a pop up says success phone is unlocked.
Step 3 getting the new esn
Go to
www.checkESNfree.com select boostmobile
Enter your old phones esn number but change the last number to something else if your last number is a 6 try 8 then hit check if it comes back clean for boost then wright it down. You may have to try a few times to get one.
Step 4
Go to
www.meidconverter.net
Enter your esn you just got hit convert
Wright down the esn (dec) and (hex)
Step 5
Go to DFS DEMO
Click ports click samsung usb port
Go to program tab above program is the spot for your spc code enter your msl code then hit the play icon then the play icon for password.
Go to were it says serial numbers
Enter the hex and dec numbers you just got from the converter hit write. On the right side by the top says reset hit it your phone should reset.
Step 6
Need wifi to activate keep phone pluged in to pc go to boost mobile go log in to your account and click change headset put.in your new esn and hit send and bam go to go!
USE AT OWN RISK NOT RESPONSIBLE IF U BREAK YOUR PHONE!