Would this work for a 3G?

[AyoitsRichie]

Okay so I want the 4.1 speed.

I have an iPhone 3G on 4.0 and i ONLY have a t-mobile sim card.

If i could borrow a friend's att sim card, could i do this?

1) Use TinyUmbrella to upgrade to 4.1 ( Not upgrading baseband)
2) Use att sim card to activate and then use jailbreakme.com on 4.1 ( Not sure if it works on 4.1)
3) Download ultrasn0w ( since i have 5.13.04 on 4.0, if i upgrade w/o updating baseband)

Would this all work?

[schnikies79]

jailbreakme.com doesn't work on 4.1; that loophole was closed with 4.0.2. The newest redsnow *kinda* works with 4.1, but there are problems being reported (cydia not working, phone.app missing, etc.)

As of now, there is not a good jailbreak for 4.1 on the 3g.

[holl0wm1nd]

You're stuck until an official jailbreak for 4.1 is released.
There's nothng to do for now.

[iYeow]

You should not restore to 4.1, no jailbreak. If you want speed, downgrade to 3.1.3 again.