Applies to following iDevices:
Since the releases of iPhone 3GS (MC model) Apple start signing the firmware device. It means that Apple must accept the firmware that you want to install on your iPhone 3GS. This means you can only install the most recent version of OS!
The signature (Known as SHSH) is a kind of hash code stores in a file with XML format that generate for your device. Apple uses your device ECID and firmware version in order to create that.
So if you know your ECID and send it to Apple, their servers (known as TSS server) send the code (SHSH) back to you (Remember you just can get) so you can store it somewhere. Firmware Umbrella can do it for you (I will talk about this later on this article). Read the rest of this entry »
