Thinking of Jailbreaking...

Discussion in 'Jailbreaks and iOS Hacks' started by andy9l, Oct 17, 2010.

  1. andy9l macrumors 68000

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    Aug 31, 2009
    Location:
    England, UK
    #1
    Firstly, I apologise for my lack of knowledge on this matter. It's not something I've looked into in the past 2.5 years I've been using iDevices.

    I understand that a new 'Greenpois0n' application can be used to 'Jailbreak' my iPhone 4 running iOS 4.1. I understand the term Jailbreak (in a simple form), and understand that it does/may void my warranty. There are a few things I'm unsure about and are putting me off trying this craze...

    1. I do not rely on an 'unlock'. My iPhone is locked to O2 - I use an O2 SIM card, and have a contract with them. I'm happy with that. Does this mean I can skip the bit about preserving my baseband? Or backing up my 'SHSH blobs'?

    2. Once Jailbroken, does iTunes work as normal with the iPhone? i.e. Sync with Music, etc.?

    3. Is it really worth it? The primary reasons I'm looking at Jailbreaking are for the Wi-Fi hotspot apps, and the swish looking themes you can install.

    4. Does clicking 'Restore' on iTunes (with a Jailbroken iPhone) bring back a completely fresh iPhone 4 again? i.e. No Jailbreak trails/apps left on there?

    Essentially, I'd like to try it. But Apple being Apple will kick me whilst I'm down if I manage to screw it all up. I'm a cautious guy - especially when I'm paying £1000 for my mistake.

    Thanks in advance for any advice/guidance, much appreciated.
     
  2. celticpride678

    Joined:
    Feb 15, 2009
    Location:
    Boston, MA
    #2
    1. Preserving your baseband won't be necessary then. SHSH blobs are what allow you to downgrade your iOS version, despite Apple not letting you.
    2. Yes
    3. If you think you'll you the extras you'll get, go for it.
    4. Yes, but you must restore as a clean device (iTunes gives you the option later in the restore process).
     
  3. andy9l thread starter macrumors 68000

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    Aug 31, 2009
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    #3
    Thanks for your response.

    Regarding #1 - should I try to grab my SHSH blobs then or will I be fine without them? I have no intentions to downgrade since I don't rely on unlocking my iPhone.

    Chances are that I will restore my iPhone as new after trying the Jailbreak - I just want to have the chance to give it a go.
     
  4. troy14 macrumors 6502a

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    Mar 25, 2008
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    Las Vegas (Summerlin), NV
    #4
    I would save your SHSH hashes no matter what - if you ever resell your phone, etc, it'll help the resale value. It doesn't hurt your phone and it takes about .5 seconds to do so. No reason not to.

    You can jailbreak your phone, do whatever you want, then do a restore and Apple will have no idea that you jailbreak your phone (as long as you do the 'set up as a new iphone' after done restoring and do not restore from backup)
     
  5. eastercat macrumors 68040

    eastercat

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    #5
    SHSH doesn't really have to do with your ability to unlock*. It's about your ability to stay jailbroken.
    For example, let's say Apple releases iOS 4.2, but the jailbreak only goes up to 4.1. If you upgraded to 4.2 and you didn't have your SHSH for 4.1, you would have to wait until the devteam came up with a jailbreak for 4.2 (if they decided to release one). If you really like those themes and tethering programs, you'll be unable to use them if you're stuck on a non-jailbreakable iOS.
    However, if you had your SHSH for 4.1, you would be able to downgrade to 4.1 and re-jailbreak again.

    *You are able to use SHSH to keep your baseband (which determines unlock) from being upgraded. That's about the extent of involvement of SHSH with unlocking.
     
  6. andy9l thread starter macrumors 68000

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    #6
    Thanks for both the responses.

    I still don't quite understand the point of grabbing the SHSH blobs. I understand that they can be used to allow me to downgrade the iPhone, but surely I can avoid having to do this by simply not upgrading it (to a non-Jailbroken version) in the first place?

    The only use in my case I can see for them is if something goes wrong and I need to restore the phone - iTunes will force me to download the latest which may not be 'Jailbreak-able'.

    I will keep them nonetheless - I would just like an explanation as to why people upgrade their Jailbroken phone only to downgrade again.

    Do you need to Jailbreak your phone every iOS update? What happens to your Cydia apps?

    I apologise for all the questions, just want to be thorough and not miss a detail :)
     
  7. localboy28 macrumors 6502a

    Joined:
    Jul 27, 2010
    #7
    SHSH files are saved because sometimes a restore is the only option
    And restore usually means goodbye jailbreak.
    But with SHSH on file you can revert back to previous versions and jail wreak anytime.
     
  8. andy9l thread starter macrumors 68000

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    #8
    Right, so it's primarily as a backup plan? If something goes horribly wrong and I have to restore, I can use the SHSH blobs to restore to a previous version - one that can be Jailbroken.

    Edit: Any suggestions on limera1n or greenpois0n? Both seem to have very respectable developers.
     
  9. Justinb51 macrumors 6502

    Justinb51

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    Apr 9, 2010
    Location:
    Indianapolis, IN
    #9
    Yes every time you do an upgrade you will need to rejailbreak because the software upgrade from apple wipes out the jailbreak. As for the ssh blobs, it's just a good idea and takes no time and just one click on the screen, you never know what apple might do and this may save you some heart ache.
    After any IOS update you do, when your Jailbroken, you have to rejailbreak, as I said above, if you want to keep your cydia apps you need to get a program such as aptbackup or pkgbackup. This makes a list of the things you have installed from cydia and then puts them back on your phone after you rejailbreak. Pkgbackup cost $4 or 5 but I am told works well and is worth it. I used aptbackup last time I upgraded and rejailbroke and had many issues, I do not recommend aptbackup.

    Hope this helps.

    I used greenpois0n for my most recent JB with no issues so far, but many have used the other with no issues. I guess i just prefer CDT.
     
  10. andy9l thread starter macrumors 68000

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    #10
    Thanks for your informative response - much appreciated. I've downloaded both greenpois0n and limera1n and greenpois0n looks a lot more trustworthy (purely on an interface level!) so I'll go for that one.

    I've just opened up TinyUmbrella and have saved my SHSH. It has edited my hosts file and has appended the following to it:

    Code:
    74.208.10.249 gs.apple.com
    Will this line prevent me from 'officially' restoring? i.e. after Jailbreaking (and after this hosts change has been made), does the iTunes restore still operate as normal - connecting to the Apple servers etc.?
     
  11. Justinb51 macrumors 6502

    Justinb51

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    #11
    Every time you restore iTunes checks with apple to make sure the firmware you are trying to restore to is a valid and current signed package. I believe that by adding that line iTunes thinks it checking with apple but is in fact not, and iTunes is checking with cydia ot TU. iTunes still get the "ok" to allow the restore.

    I have never had to use this so I cannot comment on the exact process. I also have never used TU. I usually just back up my ssh blobs in cydia. When you get in to cydia the first or second time there will be a link that says something about "make my life easier". When you click that link it backs up you ssh blobs on cydias server.
     
  12. andy9l thread starter macrumors 68000

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    #12
    Thanks Justin.

    To clarify, removing that line from my hosts file and clicking 'Restore' on iTunes will restore my iPhone to the latest iOS version (whatever that may be)?

    Basically what I'm trying to ask is; if I Jailbreak and give Cydia my SHSH blobs (in-case I ever need to restore to iOS 4.1) - can I just forget it all ever happened and restore back to an iPhone 4 running the *official* iOS 4.x using iTunes? (Assuming my hosts file is restored to it's original - I've got a backup of the original and know what I'm doing with that stuff.)

    I understand that I cannot update the iPhone without losing the Jailbreak (until a new one comes about for that iOS version), and am happy with that.
     
  13. Justinb51 macrumors 6502

    Justinb51

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    #13
    Hey at this point I have pretty much exhausted my knowledge base on the subject and I am not 100% sure. I would assume that you would in fact have to remove that line if you want the official version of the newest iOS, so that it checks with apple. I do know, or have read many times, that to remove the jailbreak all the way you need to set up as a new phone and not from a backup because in your backup file there is info (data) from the jailbreak.

    Also just FYI how it was before greenpois0n, when apple came out with a new iOS and you installed it, you had to download the old firmware off the net and use the ssh blobs to install it on the iPhone if you wanted to go to an older firmware, that's where TU and the ssh blobs come in to play. That was because the new firmware was not jailbreakable (yet).
    From what I understand now with this new jailbreak, greenpois0n and limera1n, the way it actually does the jailbreak it doesn't matter what apple does, any firmware is jailbreakable (4.2 etc. ) on your current idevice. From what I have read any new devices that comes out from now on may not be able to be jailbroken with the current jailbreak if apple closes what ever exploit they are using. The current exploit is not firmware dependent its device dependent. ***I think from what I have read***
    As I said above this info is from what I have read and not personal knowledge. SOMEONE PLEASE CORRECT ME IF I AM WRONG!!!

     
  14. eastercat macrumors 68040

    eastercat

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    #14
    If you want to erase all traces of your jailbreak, you restore the phone. However, you won't be able to restore from back up. Any backup made during your jailbreak days will retain a trace of the jailbreak. You'll have to set up as new.

     
  15. andy9l thread starter macrumors 68000

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    #15
    Thanks for the responses.
    I think I'll just go ahead and use Greenpois0n and give Cydia my SHSH blobs. Thanks again to all who responded :)
     
  16. eastercat macrumors 68040

    eastercat

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    #16
    You should also use Tiny Umbrella for your blobs. You'll have a local copy on your computer. IMO, it never hurts to have a copy on the computer.
     
  17. Night Spring macrumors G5

    Night Spring

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    Jul 17, 2008
    #17
    Nope. I've restored to new official firmware without removing that line. That line sends iTunes to Cydia instead of Apple, if iTunes asks for a sig for a new firmware, Cydia passes on the request to Apple, then relays the sig back to you, while also saving the sig at the same time.

    But if you want to "remove" it, there's no need to actually remove it, just put a "#" at the beginning of that line. That disables the command. Then when you want to restore to an older firmware, just delete the "#".

    Not quite correct either. Even with greenpois0n and limera1n, new firmware will not be automatically jailbreakable. It is assured that the Dev Teams and/or Geohot will be able to write a new JB program for newer firmware (at least for the current existing hardware -- if Apple revises the hardware, all bets are off), but we end users would still have to wait for them to release the new JB.

    Also, if you save the ipsw file for each firmware whenever you update and install new firmware, you don't have to download them again each time you want to downgrade.
     
  18. Justinb51 macrumors 6502

    Justinb51

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    #18
    To night spring, thank you for the above clarification!
     
  19. sammy.d macrumors regular

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    Jun 18, 2010
    #19
    Hi guys,
    I'm a bit like andy and want to be very thorough and just have a couple of questions.

    1. If I jailbreak and then decide to restore to the official ios (or update to a non-jb version), can I get back all of the apps that I have at the moment (im not jb). Does itunes keep all of my data backed up?

    2. If I jb, does itunes keep the jb data backed up and overwrite my non jb backups?

    3. Can I use the non-jb apps i have atm on a jb phone? (I assume you can't use jb apps on a non-jb phone)

    It may sound confusing, but I am confused.

    Thanks. :)
     
  20. Night Spring macrumors G5

    Night Spring

    Joined:
    Jul 17, 2008
    #20
    From http://www.hackthatphone.com/4x/read_me_first.html

     
  21. andy9l thread starter macrumors 68000

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    England, UK
    #21
    Thanks Night Spring :)
    I'm trying to get some things together (well, a theme) before going ahead. The theming capabilities is the main reason I'm looking into this as I've said before.
     
  22. Big Ells macrumors 6502

    Big Ells

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    London, UK
    #22
    I was much like you Andy, but once i started SSH'ing themes and playing around to make my iphone 'mine' i couldn't see myself going back. Macthemes is a great site for new themes and icons, but will require you to be able to ssh (many how to's online and is very simple)

    Good luck and see you on the other side ;)
     
  23. nebo1ss macrumors 68030

    Joined:
    Jun 2, 2010
    #23
    If you restore an ip4 without removing or commenting out the host file change that TU makes you will restore through Saurik and get a 1004 error because the baseband signing will fail and you will have to kick it out of recovery with Tiny umbrella, it will also save the old baseband. If the op wants to restore through apple he must remove or comment out that line.

    This is unique to the ip4 because of the baseband signing and is the same reason why tiny umbrella saves the old baseband. It is not what Tiny Umbrella does that keeps the old baseband, it is what it does not do "sign the baseband".

    This failure might scare the op since he is not used to JBing and he should be aware of it.
     
  24. andy9l thread starter macrumors 68000

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    #24
    Thanks for your response nebo1ss.

    I've removed that line in my hosts file and completely removed TU. I'm happy to just restore back to non-JB iOS if anything should go wrong - but I will give my SHSH blobs to Cydia when it asks 'make my life easier' in-case I change my mind. I have the line saved so I can add it to my hosts file if I choose to. I really don't like TU - it seems very intrusive.

    So if I do as described above, I can restore via iTunes normally to get a fresh iOS 4.x install? This is the most important thing to me. If I can't forget all about the Jailbreak when I choose, or if I can't get my phone/Mac/iTunes back to normal - it's not worth it for me.
     
  25. Night Spring macrumors G5

    Night Spring

    Joined:
    Jul 17, 2008
    #25
    Yes, exactly. You can always go back to factory state by restoring.
     

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