iPhone Jailbreak only for this scenario... Am I correct?

[hansgmuny]

iPhone 3G
unlocked and service with tmobile currently.
iOS 4.2.1
BB 5.15.04
Win XP pro SP2

from all the reading online i have hopefully reached the right conclusion.
all i want is a jailbreak. since i am already unlocked and have service w/tmobile, i shouldn't have to upgrade to iPad BB 6.15 for the unlock. but i am not absolutely certain.
considering all the little things that seem to pop up, i was hoping to get validation either or.
if i can just do a jailbreak any suggested program.

 

[Applejuiced]

Since its unlocked do not install the iPad baseband.
Just jb it.

 

[hansgmuny]

Applejuiced,

thanx 4 your reply.

If I am going to use redsnow for the JB do I have to use a custom IPSW in order not to upgrade the baseband?

 

[Applejuiced]

Nope.
You don't need to worry about the baseband or a custom ipsw.
Your iphone is unlocked and it will stay unlocked forever no matter what baseband you're on.

 

[hansgmuny]

Much appreciated

Have a good evening.