Unlocking sim for 5.1

[the imagineer]

Hello everyone.

I have been trying to run ultrasnow in cydia on a 3gs with 5.1 (tethered) but it seems i cant

is there any way i can unlock my sim using a BB restore or something?

Can anyone tell me what i need to do?

Thank you.

 

[Jmills87]

There's no way to downgrade baseband, if you have a 3Gs manufactured before the 35th week of 2011 you can install the iPad baseband in order to unlock.

 

[the imagineer]

serial is 86952 ect ect. does this mean week 52? if so does that mean i cant unlock?