Need help jailbreaking iPhone 3g

[sauca001]

I updated my iPhone 3g to ios 4 about a month and a half ago. As soon as I did I decided to jailbreak. Battery life was terrible and it froze all the time. I downgraded back to os 3.1.2 and my 3g is fast again, the only thing I can't jailbreak it. I've used blackrain and redsnow and both programs say my got jailbroken , but when it reboots there's no signs of it being jailbroken, cydia is not installed, someone help please I want to jailbreak my iPhone 3g

[jkmonkey]

Use spirit to jailbreak on 3.1.2 or 3.1.3.

[korin125]

Either spirit or jailbreakme.com, blackra1n is very old in the jailbreak world.

[i.Annie]

If you dont have an official carrier's SIM for Spirit or jailbreakme, redsn0w will do. But make sure youre using the right version. Redsn0w 0.9.3 for 3.1.2.