I am running Win7 x64. I would like to update both phones to 4.2.1 and jailbreak. Should I keep them at the present baseband to keep them unlockable in the future? 1. How do I jailbreak my iPhone 3GS while preserving baseband? It is currently jailbroken at 3.1.2 with modem firmware 5.11.07. Do I save SHSH using TinyUmbrella, shift restore using 4.2.1 firmware, then run redsn0w? 2. How do I jailbreak my iPhone 4 while preserving baseband? It is currently jailbroken at 4.0.1 with modem firmware 1.59.00. Do I just use TinyUmbrella + limera1n? If so, do I need a custom firmware or just the stock 4.2.1 from felixbruns?