I just want to understand this I have 3gs & 3g originally were locked to ATT but now I am using it in Canada I want to restore to 3.1.3 or to 4.0.1 so after i complete the restore do I need to activate the iphone? If yes if I have an older not in service ATT Sim card will I be able to activated so I can JB and unlock again
That AT&T SIM will be good for you. That means you can avoid hacktivating which means you will avoid many problems it could cause.
Your 3G is easy. Use Sn0wbreeze 2.0.2 to create a custom 4.1 fw which you can shift+restore to to preserve the baseband and maintain your unlock. You'll wanna use expert mode and make sure "activate" is NOT selected so that you can manually activate in iTunes. On a 3G, if you want iOS 4, 4.1 is best for it. After the shift+restore to the custom fw, just plug into iTunes and activate with the SIM.
As for the 3GS, it can get complicated. You'll need to specify what fw it is currently on and what you jb it with. It'll be easiest if you have a Mac, since I'm assuming you want to preserve the baseband to unlock.
"Anniex423" thank you so much for your responce - I can use AT&T SIM to activate even if the ATT&T SIM card is out of service for few month
Thanks again