Can you go from 3.1.2 to 4.0 on 3g?

[amandarenee]

I experienced way too much drama last week trying to restore my 3g and get Cydia to work so now i'm just a tad nervous about switching to 4.0. Im currently running 3.1.2 w/ a 5.11.07 baseband and a 5.9 bootloader and on the T-mobile network. I've had success w/ blackra1n in the past. Can anyone give me any advice on what to do??

[Simon]

4.0 and up run kinda slow on a 3G so you may want to stay put.
If you really want to upgrade you can use one of these guides to do so safely so that you will still be able to unlock after:

Mac: iClarified - iPhone - How to Jailbreak Your iPhone 3G Using PwnageTool (Mac) [4.1]
Windows: HOW TO: Jailbreak iOS 4.1 with Sn0wbreeze 2.1

[amandarenee]

if it's slow, i can hold off. this 3.1.2 isnt killing me. But i'm curious to try it and i can always downgrade back down to 3.1.2 right?

[Simon]

Yes, a 3G can always go back to a pre 4.0 firmware.

[Tazz229]

Will it not jailbreak with limera1n then?

[Simon]

Limera1n does not support iPhone 3G.

[amandarenee]

i think my only concern is losing the baseband..

[CaptainChaos]

Use a custom firmware that has been created with Pwnage Tool 4.1.2 and shift/restore to it in iTunes. You will preserve your baseband that way. If you do not have a Mac, you can find custom firmwares through Google. Make sure it is a 3G firmware.

[Tazz229]

That was my concern too but I updated using tiny umbrella no problem. As long as tiny works with the 3G you shouldn't have a problem I can post the info if you like.

[Simon]

Tiny umbrella only preserves baseband on a iPhone 4. For all other devices a custom firmware is needed.

[Tazz229]

Agh ok