Here comes the news for all waiting for (untether) jailbreaks; Saurik, Cydia’s founder, now starts caching SHSH Blobs for 5.0.1 that allows you to downgrade from the updated iOS version to the jailbreakable 5.0.1.
Several people out there never noticed until they saw 5.0.1 signatures are present already in Cydia server cached SHSH for them.
What are SHSH Blobs and why they are been saved in Cydia? They are just signature files which are verified against Apple servers to assume the latest firmware is running on your device. The major thing is that it allows users to restore to an older version of iOS by downgrading the firmware, otherwise its very not possible to downgrade anyway.
Example : Apple released the latest iOS 5 firmware in the past, and you updated your device to that, after some days, the fruit company rolled out an iOS 5.0.1 OTA in iTunes that ask you to upgrade, then you have mistakenly updated to 5.0.1 iOS version. Now the important thing comes out, if you want to downgrade iOS 5.0.1 to 5.0, 4.3.5,4.3.4 or to a lowest version, then you need to have saved SHSH Blobs of the lower iOS version on your iDevice. That is the only way you can downgrade or you will be stucked there, means iOS 5.0.1. Pod2g announced that he has found an exploit few days ago in iOS 5.0.1, he also demoed a video on how he jailbroken iOS 5.0 untethered on iPod Touch, then after some days he updated that he has completed his work on untethered jailbreak for iOS 5.0.1 on all A4 running devices (such as iPhone 4, iPhone 3GS, iPad 1, iPod touch 4G,3G) and handed over to Chronic Dev Team, and currently he is working hard on iPhone 4S jailbreak and iPad 2 untethered on iOS 5.0.1, which will coom soon.
Apart from this a partial digest of a firmware file to Apple is updated by a response protocol which leads to a decision to go on with the restore or not. Now SHSH Blobs are cached efficiciently, which makes the process to be bypassed, verifying restore via Sauriks servers.
While this time makes every one happy, Cydia perfectly started to cache SHSH Blobs since we are near of an iOS 5.0.1 untethered jailbreak using Greenpois0n by Chronic Dev Team after which Apple will attempt counter this exploit by releasing iOS 5.0.2 or 5.1 or 5.2 in the future.
You having these SHSH blobs saved on Cydia helps you to downgrade back to iOS 5.0.1 to get the jailbreak again.
An alternative to Cydia automatically performing this process is using the tool created by @ih8sn0w called iFaith which is dubbed as the first public SHSH dumper which allows users to dump the SHSH signatures of a devices current running firmware. Whilst similar in end result to methods like Cydia and TinyUmbrella, iFaith goes that step further and allows actual physical retrieval of the SHSH blobs.
How you can save 5.0.1 SHSH Blobs on Cydia; there isn’t any steps, why? Because Cydia will now save your SHSH Blobs for iOS 5.0.1 firmware automatically, and keep in mind that these SHSH Blobs file is an unique file that you can’t use for any other iOS devices at all.
Sauriks’ Cydia is back in action seems well at the present for all jailbreaking community, a jailbreak coming and bunch of tools available for you and me to sue it.