3GS firmware downgrade to send for repair

Quote:

Originally Posted by ba5e

I will send my iphone 3GS in for repair (cracks in the plastic) and want to downgrade to the iphone os 3.0, but I am not sure right now if when I do downgrade I can restore the 3.1.2 backup (app data, address book etc.) using itunes 9.0.3 -is it possible?

here is the state of my iphone:
iphone OS: 3.1.2 (custom Pwnage tool ISPW)
baseband: 04.26.08
Bootloader: 6.4

I have a whole catalogue of old vanilla and custom ISPW's, whats the best way to proceed to restore the vanilla 3.0?

You need a SHSH for 3.0 to restore to vanilla 3.0

Any repair by Apple will result in you getting a refurbished phone, it is very unlikely they will just replace the case for you. That is not how they work.

The refurb phone might be tethered jailbreak only, it will likely run OS 3.1.2 or 3.1.3.

I would ask some very direct questions before sending a 3GS in for cosmetic repair if you rely on jailbreak and/or unlock.