How to do a clean reinstall of Iphone?

[wuitsung]

How to do a clean reinstall of Iphone? I recently upgraded to 4.2.1 and found out the baseband firmware cannot be unlocked. I tried to use pwnagetool to resotre to 4.1, but still the baseband doesn't change...... why?

[Simon]

What type of iphone do you have?

[wuitsung]

iphone 3g

[iYeow]

Shift + restore to stock firmware is a clean restore.

[Simon]

You can't downgrade baseband on a iPhone 3G, with one exception. If you have 5.8 bootloader than you can. You can check by downloading f0recast and running it with your phone attached.

[wuitsung]

thanx x98car. Even a clean install?? so you are saying I need to jailbreak and then run the f0recast and i will be able to downgrade the baseband for sure?

[Simon]

You can run f0rescast even if you arent jailbroken and it can tell you if you can downgrade baseband or not.