Recently it seems many people have discovered the Firmware Keys pages on the IPSW Downloads site. I've been getting a lot of questions about them, so here is an explanation.
Firmware keys are used by jailbreak developers to access parts of an IPSW file allowing them to do research, or modify these parts (in a tool such as sn0wbreeze).
I learnt about these when I was writing iKeyHelper - a tool which at the time (mostly) automated the finding of these keys, using the greenpois0n payload. For those curious about how this works, iKeyHelper is open source and available to download from my GitHub. Also here is a very informative article on TheiPhoneWiki.
However, iKeyHelper became redundant in February last year, after @iNeal, @iH8sn0w and I created a set of tools which completely automate the process. This tool is now integrated into fwlinks and automatically creates the page(s) that you have been visiting on this site.
So, onto the questions:
Will this allow me to downgrade my device to x firmware?
- No. If this were the case, tools would exist to do this.
Why aren't there any keys for newer devices?
- Techniques for getting these keys do not exist currently. The easiest way to get them requires a low level exploit (i.e. Not user land like evasi0n) and newer devices do not have these available. Update: keys for some newer devices have been added to the pages. Credit to @iH8sn0w and @iNeal.
Why did you make this? Surely we can just use TheiPhoneWiki?
- icj.me will get the keys first, and the format of the keys is easy to use and one that developers like. An API also exists for collecting the keys data in a JSON format (contact me if you wish to know more).
Hope this clears a few things up. If you have more questions, ask in the comments below!