Since I am getting an iPhone 4, I am having my cousin in Israel help me sell my 3GS unlocked while I am there on vacation later this summer. I still have six days (including today) before I'll have the new phone, so I'm not exactly ready to wipe my 3GS today, but I want to make sure this is possible. Can I follow all of the "Downgrade" instructions in the sticky in this forum section but simply shift click restore to 3.1.2 while 3.1.2 is currently installed? I simply want to keep the 05.11.17 baseband so the blacksn0w unlock works, as this is the most important factor if I'm going to sell my phone to an international customer. If this works, I plan to restore to 3.1.2, keep the 05.11.17 baseband, and use Spirit to jailbreak (and then install blacksn0w).