Jailbreak Noob: What are SHSH blobs?

[NoSugarJustSpice]

I am on my second iPhone and currently have the iPhone 4 currently running iOS 4.1. I am considering jailbreaking my phone, once I'm able, and have been doing a lot of research on TiPb.

Can someone explain to me what SHSH files/blobs are? I read one post of a user who had asked another (when talking about some problem after having a jailbroken phone and then updating the firmware) if they had backed up their SHSH blobs. What do I need to know about SHSH files/blobs?

I'm sorry if there was another thread about this, but I did a search of the forum and couldn't find one...

Thanks for any help in advance.

 

[big9erfan]

Think of it like this, SHSH files are a permission from Apple to install a specific version of firmware onto a specific device.

SHSH blobs are unique per phone per firmware.

Lets say a jailbreak comes out for 4.1 next week. You need to save the SHSH Blobs as well. If you don't, and a problem happens with the jailbreak, then you won't be able to restore to 4.1 and re-jailbreak once Apple releases 4.1.x or 4.2.

 

[NoSugarJustSpice]

So how exactly do you save these blobs? Are they saved when you sync your phone to iTunes, or is this a different process - something that the user has to manually save to their computer?

I'm sorry if this is a ridiculous question. As much as I'm trying to follow all of the information given for the jailbreak process, some of it is over my head and I'm trying to grasp it all.

 

[Massie]

Once you jailbreak, Cydia (the JB app store) offers the option of saving them for you. All you need to do is click the "Make My Life Easier" button when opening Cydia. You can also save them locally using the Firmware Umbrella program.

You'll only ever need your shsh if you want to downgrade?basically, when iTunes goes to "call home" to verify the software, you'll point it to your saved shsh blobs instead, either on your computer or on the Cydia server.

 

[big9erfan]

You don't have to be jailbroken to save your SHSH blobs. As Massie mentioned, you can use the Firmware Umbrella project to save your blobs on your local hard drive, you can also use that same program to let you restore to firmware versions that Apple is no longer signing, so long as you have saved your SHSH blobs.

 

[theringer]

Hi guys!



I know most of u aren't new to jb but, i'd like to tell u, i have a webapp for beginners. I hope it will be helpful for start jailbreak. Of course, all content is in english. It's called "I DO JB". I released it only 2 days ago. It tells u the most important thing what u have to know about jailbreak and cydia. This is my first webapp so pls feel free to let me know my mistakes. It doesn't require jb to install it. Thanks guys!

more spamming of your site now that you have 10 posts? Reporting this one also

 

[NoSugarJustSpice]

Thanks so much for your feedback. Your explanations helped me understand the process much better (maybe not completely, but that's not your fault!) I've still got a lot to learn but your explanations are so appreciated. Enjoy the rest of your weekend!