Can I jailbreak my stock 3.1.3 iPhone?

Dryst999

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Feb 25, 2010
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I got my iPhone 3gs a little over a month before the 4g came out and it came with 3.1.3 on it, is there anyway to jailbreak this phone? I'm reading different things and am confused about if this is possible since I have the newer broadband.

If it is possible can someone link me a tutorial or let me know which of the 1000 jailbreak tools you can do this on?
 

pm

Elite Member Mobile Devices
Jan 25, 2000
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There is no jailbreak for 3.1.3, so the answer is no. You need to be on 3.1.2 - and you can't go back because it's a new phone. And even if you could be on 3.1.2, which you can't, you (probably) have the new bootrom and the 3.1.2 hack doesn't work on the new bootrom at all.

So you need to go up to 4.0.1 (or 4.0, but Apple won't sign for 4.0, so go to 4.0.1). Follow the instructions here:
http://www.iclarified.com/entry/index.php?enid=10943

So there's three parts to an iPhone from a jailbreakers perspective:
the bootrom - this is your BIOS basically. It's the thing that runs when you put the phone in DFU mode (not sure what DFU means, but I usually think of it as "device farked up" mode). DFU mode is a special mode you can put the phone in to do restores of the firmware when the phone is totally dead and won't work at all. The iPhone hacked found a software mistake in the way that signatures were done on older iPhone 3GS's that took advantage of a problem in the old bootrom. Bootroms can't be changed (the ROM in bootrom means "read-only memory" so you can't write to it. What you get when you buy the phone is what you have forever.

the baseband - this is the communications processor. The thing that takes to cell phone towers, WiFi, bluetooth, etc. This can only be upgraded, never downgraded - why... no idea but this is how Apple made it. You can only ever go up with the phone. When you unlock a phone, you are modifying the baseband firmware - because the unlock is in the software that runs there.

and the main firmware - this is the main OS. 3.1.3, 4.0, 4.0.1, these refer to the main firmware running on the primary CPU. These can't be changed to an older version of the software unless you have the SHSH keys - which are special signature keys that you get from Apple at the time that you are upgrading firmwares (.ipsw files). But Apple will only sign the current firmwares, not older ones. So... in essence, you need to capture the SHSH keys to a firmware if you want to downgrade. If you didn't, then you can't downgrade.

So you (almost definitely) have the new bootrom, and you don't have the SHSH keys for that specific phone for 3.1.2 (so you can't go down to 3.1.2, hack, and up to 3.1.3) and so you are toast on 3.1.3 for multiple reasons. The new bootrom started showing up in all new iPhone 3GS's made from roughly Oct./Nov. 2009 onwards.

To jailbreak, you'll need up to update to 4.0.1 and then go to http://jailbreakme.com and let it do it's thing. Then run Cydia on your iPhone (or download tinyumbrella for your computer) and definitely grab your SHSH keys so that you can get back to 4.0.1 - which can be jailbroken - in the future and then you should be set.

If you want to stay on 3.1.3 - can't think why you would want to do this - and you want to jailbreak... you simply can't.

My favorite site for tutorials and explainations is iClarified:
http://www.iclarified.com/jailbreak/

And, yes, this whole thing is ridiculously confusing, and even my attempt at an explanation is likely not very readable. You get the hang of it if you jailbreak enough releases.

One last very important thing, even if you don't jailbreak and upgrade to 4.0.1 for a while, get your signature SHSH keys for 4.0.1 now for your device while you can still get them. Apple stopped signing 3.1.2 back on the 4th of Feb. So if you didn't get the 3.1.2 keys before the 4th of Feb, that was it, you couldn't ever go to 3.1.2 after 3.1.3 came out.

So regardless of whether you want the hassle of jailbreaking 4.0.1 now, get your SHSH keys now while you can for 4.0.1. Because if Apple releases 4.1 (and they will... soon, it's on Beta 3), then you will be stuck until the hackers come up with a new jailbreak (and that often months). You can't go to a version that Apple is not signing for and the jailbreak for 4.0.1 is definitely not going to work on 4.1. In summary, get your keys now... or jailbreak now. Don't wait because 4.1 could arrive tomorrow. To get your 4.0.1 keys, use tinyumbrella, or jailbreak and use Cydia.
 
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Dryst999

Member
Feb 25, 2010
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Thanks so much for your help, you pretty much clarified everything I was confused about... my googlefu just made my head hurt!
 

pm

Elite Member Mobile Devices
Jan 25, 2000
7,419
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81
Oh, yeah, I forgot. Spirit to jailbreak 3.1.3. I'm so used to the dev tools, that I forgot about Spirit.

Thanks, JohnAn2112