About SHSH backup?

[Raishi]

So it occurred to me recently that I have not backed up my SHSH and I cannot figure out how... but lets say I do find the answer before someone posts on this topic... I don't quite understand how it works.

Lets say I have to restore for whatever reason?
wouldn't that uninstall Cydia also? at which point how do I retrieve my backed up SHSH?

is there something I need to install on my computer? (just as a note I am running windows)



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Other useful IPhone Details:
3Gs
ios 4.0.1
Jail broken with Cydia
no SSH experience.

 

[maturola]

The SHSHs are just a Signed Certificate that tell iTunes that you "can" install that firmware, by Backing up those files signed by Apple you can "trick" iTunes into thinking that you are "Allow" to install that specific Firmware.

To backup your SHSH, you can do it 2 ways, one would be letting Cydia do it, now this doesn't happen on your phone, this happen on Cydia servers, Cydia take the information it needs from your phone and them goes to Apples server and ask them to sign the file and stored them for you.

You can use a Program on your computer call, TinyUmbrella to backup those files manually on your computer and them send them a copy to Cydia server also.

Now if you "just' decided to start backing up your SHSHs, you are too late for any usefull at the moment, since you need Apple server to sign them, Apple will only sign the current firmware (4.1).

 

[Raishi]

so if my Iphone has a problem and I restore to factory will it do so? or do I need to back up to restore?

is this something I may need?

 

[iPhone-power]

so if my Iphone has a problem and I restore to factory will it do so? or do I need to back up to restore?

is this something I may need?

If you need to restore, your only choice would be 4.1 firmware.

 

[Raishi]

Ohhh I kind of get it... it backs it up so you can use your jailbreak part... otherwise you can only get the up to date one which I assume most of the time, is unable to be jailbroken.

so it would not impact your IPhone in such a way as in kill the phone not let you install any firmware when you try to restore and leave you with a shell of a IPhone. <- was what I was worried about.


is this correct? or am I still missing something? (sorry I'm so noob xD)

 

[iPhone-power]

SHSH blobs or hashes are required to restore or downgrade the firmware to any version other than the current version (now 4.1).

Without hashes, no downgrade to older versions.

The exception is 3G phone to versions of 3.x.x