So I bought a new iPhone4 and want to sell my old jailbroken 3GS (on 3.0.1, 04.26.08 baseband). From what I am reading I see that it can be upgraded to a jailbroken 4.0. However, as I always recommend that folks Erase All Content and Settings before they sell their device, I'm wondering if I will be able to restore to a jailbroken 4.0? My goal is to sell the device so that it can be unlocked. If I Erase All Content and Settings, can I restore a jailbroken 4.0? If needed, I currently have all my SHSH's on file with Cydia. Any input is appreciated.