Format, downgrade, upgrade and jailbreak

[xfer]

This is quite complex so i thought i should get some advice before advancing.

My iphone 3g is currently jailbroken and is on version 4.1. It has been going very slowly, i figure it'll be good to format it.

Can i just synth it with itunes, get it upgraded there thus "unjailbreaking" it, and then getting the latest jailbreak available? It sounds too simple, i figured it would screw up somewhere.

Advice appreciated.

[xtacy]

Downgrading 3G to 3.1.3 would be advisable.
Shift restore 3.1.3 from iTunes and use spirit to jailbreak.

[xfer]

Downgrading 3G to 3.1.3 would be advisable.
Shift restore 3.1.3 from iTunes and use spirit to jailbreak.

Thank you.

So i'll restore my phone to 3.1.3, then download and install the latest version and jailbreaking with spirit? Is it advisable to do it with the latest version on itunes?

[Mes]

Note: iTunes will sync your music, videos, and apps, etc but the 'restore from previous backup' will not work because it's a higher version backup. Things like screen layout, contacts, calendar, SMS can not be restored unless they are sync'd differently - like iCal or Outlook, etc.

[i.Annie]

+1. better back everything up manually. Or upgrade to 4.2.1 but it isn't great in performance on 4.2.1. If you disable multitask and wallpaper, remove unused language packs, and turn off spotlight, the performance won't be too bad at all but it will not be as smooth and fast as 3.1.3.