Download Custom Firmware ipsw files for iPhone 2G, 3G 3.1 [Windows/Mac] , Error 1600 Solution Updated

UPDATE : A new version of custom firmware 3.1.2 for iPhone 2G/3G/3GS is now available here! UPDATE : If you get a 1600 error while trying to restore to a custom firmware here, try this. iPhone 2G and 3G users can now safely update to 3.1 firmware without updating the baseband (for unlock). If you…