Bootloader and Pwnage Question

Ill say this first, Ive read all the instructions and everything and just have a simple question.

I installed the legit 2.0 on my original 2G iPhone, when I run Pwnage it asks for the 3.9/4.6 BL files, Im just wondering real quick, if i go through with the jailbreak will it modify my BL so that my warrenty is voided? I dont want to unlock, only jailbreak since I am on AT&T.

Because it asks if the "you are a legit iphone user", thats what determins if it unlocks/changes the BL version right?