i am a noob. need help.

[tallassguan]

i'm thinking about buying a 3gs on craiglist and unlocking it myself. all i'm finding around my area have ios4 installed. i want to know if i am able to unlock/jailbreak it and how. if there is a thread to learning about unlocked and jailbroken iphones for beginners, can you link me. please and thank you.

[PWNsyst3m]

For unlocking: iClarified - Unlock Wizard for iPhone
For jailbreaking: iClarified - Jailbreak Wizard for iPhone, iPad, iPod, AppleTV
You also need to learn about shsh's: http://www.theiphonewiki.com/wiki/index.php?title=SHSH

Before I made a purchase I would ask what baseband the iphone is on and if it has any saved shsh's.

I edited the link for the shsh a couple of times. The one I have up now is an a lot better explanation.

[tallassguan]

thanks for all the links. so does it mean i have to jailbreak it then unlock it? and what if they dont have any saves shsh's?

[eyeRobot]

Yes you need to jailbreak before an unlock.

If they don't have any SHSH files saved for 3.1.x then you can't downgrade and you can't jailbreak 4.0 yet. If they have SHSH for 3.1.2 or 3.1.3 is best. You should try to check the bootrom too, old bootrom is better as you could go back to a jailbroken 4.0 after you jailbroke at 3.1.x.

It's confusing isn't it!

Short answer, best buy on 4.0 would be:
3.1.2 SHSH file saved (3.1.3 2nd best - won't elaborate here)
Old bootrom.

Most folks won't have a clue what you are asking them which probably means no SHSH files saved since they probably never jailbroke.

[tallassguan]

when i'm jailbreaking it first i would need a att sim card?

[i.Annie]

Best JB is Spirit for 3GS which does require an AT&T SIM. however, you can also get a phonebook SIM from radioshack or somewhere and use that too.

Edit: I meant 3GS on 3.1.x with no intention of reupgrading to 4.0/1.

If you do intend to go back up to 4.0 and jailbreak that, you cant use Spirit it will cause problems.

[tallassguan]

then i cant jailbreak a 3gs with 4.0.1?

[i.Annie]

Um... I dont think you understood. If you get a 3GS with SHSH blobs backed up, then yes you can jailbreak it on 4.0, not 4.0.1.

You need those SHSH files to downgrade to 3.1.x so you can jailbreak that with Spirit. But if you wanted to go back up to 4.0 and jailbreak it, youd have to use something else besides Spirit in order for it to work.

[PWNsyst3m]

The best thing to use to jailbreak to 4.0 with pwnagetool or sn0wbreeze is 3.1.2 jailbroken by blackra1n or redsn0w.