I have a brand new iPhone 3gs (new bootrom) on version 4.3.5 and bb 05.16.02. I know that to unlock this phone you need to downgrade to 4.1 using saved SHSH on Cydia than jailbreak and upgrade the baseband to the iPad's. However, I am stuck. I can downgrade but only with custom firmware made by PwnageTool. Also when I try and add the iPad baseband upgrade to the custom firmware my phone no longer downgrades. When the phone fails to restore, it comes up with an error 1015 at about two-thirds the way done. I have tried TinyUmbrella, Blackra1n and RecBoot but none of them can kick the phone out of recovery mode. Only a restore works. I know there is a way because I recently bought an unlocked iPhone 3gs and according to the serial it is only a month old so it has the new bootrom. Does anyone know the method? I am working on a Mac but could get access to a Windows if needed. And I am just curious, should I be able to downgrade to stock firmware if I have the SHSHs from Cydia? Thank you to anyone with any advise.