I have an iPhone 4 running iOS 4.3.3. I use it with a Turbo SIM and need to preserve my baseband to run iOS 5. I would like to upgrade to 5.0.1. I’ve followed numerous tutorials online, and the part where I always get stuck is introducing the ISPW of iOS 5.0.1 to Redsn0w. Redsn0w always comes back saying the firmware is unsupported. What am I doing wrong? What can I do for updating iPhone 4 to iOS 5.0.1 while preserving the baseband? Is it even possible? Please help. Thanks.