I have an iPhone 3GS with the latest bootrom currently on 4.0 that I need to take down to 3.1.3, which is the latest that I was on cydia. I am pretty sure that my SHSH is on file because I had installed cydia previously. I have added 126.96.36.199 gs.apple.com to my hosts file and I have downgraded to itunes 9.1. When I try to go through DFU mode and restore a 3.1.3 ispw, it says this device is not eligible for the requested build. Am I doing something wrong? I am on win7 64bit so is my hosts file somewhere else maybe? Do I have to edit my hosts file differently?