I have a jailbroken and unlocked iPhone 3GS (3.1.2 & 05.11.07) which has a few phone numbers and sms stored. Cydia, Rock and BlackRa1n icons are also there on the Springboard. I am selling it tonight and have to clear off all the stored content. Can I use the Erase all Content and Settings to do this? Will this not impact the jailbreak (Cydia, Rock) and unlock?