For those who don’t know what’s this for.. Apple has added a new security system called ECID. The Exclusive Chip ID or ECID, is an identifier unique to every unit. ECID looks like this: 00000XXXXXXXXXXX (hex). Please be aware that some tools display the ECID in decimal format. iPhone 3GS, iPod Touch 3G, iPod Touch 2G MC and almost every upcoming iDevice is affected by this security.
Once someone updates his iPhone 3GS, iPod Touch 3G, and iTouch 2G MC to latest firmware without saving SHSH on file they not only lose their jailbreak but also the ability of downgrading to the older firmware. But if you have ECID SHSHsaved for an older firmware, you’ll always be able to restore back to that firmware and then jailbreak your iPhone.
The ECID is a very important element in the SHSH Protocol
For Jailbroken iPhone/iPad
Now that you’ve a jailbroken iPhone or iPod Touch; Launch the Cydia. Check if there’s any mention of “this device has SHSHs on file for iPhone OS: 3.0, 3.1, 3.1.2, 3.1.3” at the top of the Cydia home screen. If there is, then you don’t have anything to do. You may not have saved all SHSH on file but it’s Ok to have the latest one. Current latest firmware version is 4.3.3, so make sure you have that one mentioned there. Checkout the screenshot:
If you already have saved your SHSH on Saurik server you need not to repeat the process every time. If there’s nothing mentioned at the top of the Cydia home screen, Scroll down the Cydia Home Page and look for “make my life easier” and tap on it. This will automatically save your ECID SHSH on Saurik’s server. To confirm, simply close and re-open the Cydia and see if there’s a mention at the top now!
That’s it, you don’t need to do this for each new firmwares, Cydia will automatically save ECID SHSH of future firmware for you.
For a jailbreak free device, you can use TinyUmbrella before too late or using iFaith utility. You can save ECID SHSH on file only for that firmware version that Apple still signs, currently it’s 4.3.3 for iPhone. It is very important to keep doing this for every firmware version that comes out after these!!