What is the latest week to downgrade iPhone 3GS
 

What is the latest week we can downgrade iPhone 3GS and install iPad baseband to unlock? I did my phone with 35 weeks and my iphone dead (no WIFI, no Baseband...) Apple replace another one but still on week 30. Can I downgrade and unlock? and what's the latest week we can do?

Thanks

any body knows? I couldn't find any of this info on the net yet