Restoring a Backup after Downgrading

[ccoltmanm]

My sister has an iPhone 3G running 4.2.1. It is painfully slow. I told her i can downgrade it to 3.1.3 and it should be faster.

She said, okay, and I did it. Then, i found out I can't restore a 4.2.1 backup on a 3.1.3 restore.

She has a lot of contacts, etc. that she doesn't want to put back in manually.

My question is, how can I restore a backup from 4.2.1 to a 3.1.3 restore? Do i have to do it manually using something like iPhone backup extractor, or is there an automatic way of doing it?

She does not jailbreak, so those apps are not an option.

[j3st3r]

when the restore is done and iTunes asks if you want to setup as new or restore from backup there should be a drop down selector beside the restore from backup option, select a backup date that was done before you updated to 4.2.1

[Kioes]

plug in the iDevice then right click on it and select restore from backuop, select which backup if this does not work upgrade to 4.1 and tell her not to use multitasking, that is what slows the 3G so much,

personally my 3G is on 4.1 and i dont use multitasking, sure its a tiny bit slower then 3.1.3 but barely ever noticable.