iPhone 3G downgrade from 4.0.1 to 3.1.3

[Ethan_Hunt]

Hey guys, I'm planning to get a iPhone 3G from a friend of mine. Before purchasing it, I need to know if it can be downgraded to 3.1.3, since I have heard that the iOS 4 is very laggy on the iPhone 3G. So would want to know if I could downgrade to 3.1.3 or a more stable firmware and JB it.

Does downgrading firmware kill the network unlock? I mean it's already unlocked, so just to confirm, this process won't lock it again, right?

 

[titana]

it should be possible..you can restore it to lower firmware and then jailbreak and unlock it..i am using 3g model and recently downgraded to 3.1.2 from 3.1.3. and was able to jailbreak and unlock it.

whats the baseband of the phone you want to buy(i do not think even that matters )..i think all 3g phones can be reverted back to older firmware except for the baseband..

 

[Ethan_Hunt]

What's a baseband? iPhone newbie here.

 

[Sanav3]

I have a Iphone 3G with OS 4.1 (much better and usable in comparison to iOS 4.0 on Iphone 3G) and basebad 5.14 and the only JB and Unlock available would render its GPS unusable, so tips please for a downgrade..

 

[titana]

did you guys try this..

How To Downgrade iPhone 3G From iOS 4 To iPhone OS 3.1.3 – iPhone Hacks

however the baseband will not be downgraded and the unlock presently available will not allow you to use GPS, you might have to wait for further unlock updates for that..downgrading will however address the lagging issues on the phone..