I never had luck doing this, even using sps program and flashing the radio. I did this for a few Impala's and it never worked for me. It's suppose to work after you flash the radio or do it with a Tech 2. Some Launch Tools have the option to change the VIN, but again, I have done this before and still no radio unlock. Maybe I did something wrong? This was years ago. Haven't had the chance to do another one yet. :(

Hi Mexi, are you in the US? I never had a problem flashing used radio's with SPS here
in the US.
I heard that there is a 800 number that you can call to get the radio unlock code but I
lost the number. But flashing with SPS allways worked for me.

Check YouTube out on this. Theirs several videos on this.