I'm currently using a Blackrain JB'n 3GS on 3.1.2 with old bootrom. My new iPhone4 is coming tomorrow and I'd like to use it on a trial basis to see if it warrants trading up from the 3GS (keeping my 3GS in case I decide not to keep the iPHone4). Can I just deactivate the 3GS and start using the iPhone4 but then be able to deactivate the iPhone4 if I don't like it and reactivate my 3GS and keep the jailbreak intact? Or should I wipe the 3GS and rejailbreak it before I activate the iP4, and be able to reactivate the 3GS later or resell it on eBay? Also, if I have to install iTunes 9.2 to use the iP4 will 9.2 be compatible with my JB'n 3GS if I decide to go back? Thanks for any insight.