Firmware Umbrella Requests iOS SHSH signatures for firmware restores from apple. This allows you to downgrade to any iOS version by saving your SHSH on your local machine, and fooling iTunes to continue restoring your iDevice to any iOS version that you have the SHSH for. Apple only allows you to restore to the firmwares they 'sign'. This 'signing' only lasts for a limited time. Once they stop 'signing' the SHSHs for a firmware, there is no way to restore that firmware ever again, so saving your SHSH file allows you to always restore to previous iOS versions regardless of what the current version is. You can also use Firmware Umbrella to block the upgrade of your "Baseband" (cellular modem software) version. This allows you to preserve unlockable basebands, while upgrading to the latest version of iOS. Our resident jailbreak video expert Reza brings you tips and tricks to help you get the most use out of your jailbroken iOS device. - http://www.youtube.com/rmalayeri
