iphone 3g downgrade from 4.2.1 questions

[van30]

Hello all,

Hopefully users here can answer some of my questions.

I just got a used iphone 3g from a friend who was good about regularly updating the phone.

It is current firmware is 4.2.1
Baseband firmware is 05.15.04

I want to downgrade to the 3.1.3 firmware, and keep it there as it is incredibly slow on the 4.2.1 firmware. I don't want to jailbreak (if thats the right word for it) or use cydia etc.

I read through these instructions on lifehacker: How to Downgrade Your iPhone 3G[S] from iOS 4 to iOS 3.1.3[s]-from-ios-4-to-ios-313

The only thing is that it doesn't seem to address any things about the baseband. Is there a specific baseband that should be paired with 3.1.3? Does the version of the baseband even matter for pure downgrade purposes?

Any advice/pointers would be greatly appreciated.

Thanks!

[calandval]

you dont need to worry about the baseband. just downgrade to 3.1.3

[iYeow]

Baseband cannot be downgraded unless you have a bootloader of 5.0.8. Iforecast can detect what bootloader you have.