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Discuss Upgrading a 3GS to iOS v4.2.1 from 4.0.1 with a safety net at the iPhone 3GS - Hackint0sh.org; I have a 3GS (old BB currently at v 4.0.1 & BB 5.13.04 that I ...
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    Default Upgrading a 3GS to iOS v4.2.1 from 4.0.1 with a safety net

    I have a 3GS (old BB currently at v 4.0.1 & BB 5.13.04 that I have successfully unlocked several times with either Jailbreakme or Pwnagetool and ultrasn0w. I have looked at the features of the various iOS versions since 4.0 and might like to try AirPrint. I usually upgrade to a new iOS version ONLY when it offers features that I find worthwhile. I upgraded to 4.1 but had severe battery drain problems so I returned to 4.0.1, which works as expected. My questions are about upgrading with the ability to return to 4.0.1.

    FYI I have saved all my SHSH blobs back to 4.0 using TinyUmbrella (actually I had them earlier than that but they're now irrelevant given my bb). I have also created custom ipsws for 4.2.1, 4.1, and 4.0.1 with Pwnagtool but have not yet installed these on my phone (except 4.0.1). So my questions are:

    1) Are there any known problems associated with 4.2.1 on a 3GS that would preclude my doing the upgrade? I fortunately was able to escape from 4.1 when I couldn't find an acceptable solution to the battery drain problem.

    2) How can I save the backups for the various iOS versions so that I don't have to spend hours restoring apps, music, emails etc. When I sync my phone, iTunes reports that it's "backing up" my iPhone's data. What exactly is this backup? Can it be captured, saved, and used to "restore from backup" so that if I upgrade to 4.2.1, decide I don't want it and then return to 4.0.1 I won't have to set up as a new phone? (Yes, I realize that it's iOS version specific). If not, how do I backup the contents (personal settings, apps, etc.) so I can gracefully restore my phone to it's current state if something goes wrong?

    I assume that the purpose of my creating custom ipsws is that it won't upgrade my BB (I want to STAY at 5.13.04 for the time being). if I want to return to an earlier iOS do I put the phone in DFW mode, option+restore it from iTunes. When it asks for restore from backup can I do this? I would really like to avoid completely reconfiguring the iPhone if I can.



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    Super Moderator Array Olethros's Avatar

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    SAM fixes most battery drain problems. The idea is that it tricks iTunes into thinking you are activating your phone with a SIM card from the carrier your phone is supposed to be locked to. You can play with SAM on your current OS if you want, just be sure to keep a way to SSH into your phone (in case you have problems) as that can be a good way to avoid restoring if for some reason you screw things up playing around with SAM.

    Apple is most probably working hard to find a way to block SAM. They have blocked other techniques used to get legitimate activation.

    You can "restore from iTunes backup" after you reload the iOS version, however a backup from 4.2 can't be restored on a device running 4.1 (for example). The other way (backup of older iOS version restored onto newer iOS version) works
    Each backups is saved as a folder containing many hundreds of files, you can simply copy this folder and it's contents to make a "backup of your backup"
    iTunes generally only keeps a backup from the last time you synced/backed up your phone.
    Restoring your phone and "setting up as new" will overwrite any previous backups you might have made.

    if you are careful with making "backups of backups" and you stay with the latest iTunes version you can definitely downgrade the OS and restore from the backup that matches your destination OS.

    To downgrade, you don't specifically need DFU mode. What you do need is to ensure that iTunes can find your saved SHSH and option-click restore in iTunes, then browse to the appropriate custom IPSW that matches your previous iOS version.
    Once the restore is done, you can select "restore from iTunes backup" and then select the date/time you made a backup for that particular (or older) OS.

    Just to be clear, a tiny percentage of people have experienced problems after "restoring from iTunes backup" where the backup was made on a jailbroken/hacktivated phone.
    My personal approach is to "restore from backup" for Y.x.x updates but always set the phone up as new when going to a major new iOS version (eg from 3.x to 4.x).
    Even Apple recommends "set up phone as new" as a valid troubleshooting step if you still experience problems even after a OS restore and a "restore from iTunes backup"
    Please read the stickies & search forum before posting!
    How to report an iTunes restore/update fail in a useful manner
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    iPad 3G 64GB (4.3.3, Redsn0w) oldest SHSH 3.2.2
    iPhone 4 32GB (4.2.1, Redsn0w JB-monte) oldest SHSH 4.1
    iPhone 3GS 32GB (4.3.3; Pwnagetool) factory unlocked oldest SHSH 3.1
    iPhone 8GB (3.1.3; Pwnagetool) AT&T Locked - Unlocked with bootneuter

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    Quote Originally Posted by Olethros View Post
    SAM fixes most battery drain problems. The idea is that it tricks iTunes into thinking you are activating your phone with a SIM card from the carrier your phone is supposed to be locked to. You can play with SAM on your current OS if you want, just be sure to keep a way to SSH into your phone (in case you have problems) as that can be a good way to avoid restoring if for some reason you screw things up playing around with SAM.
    I believe it was you or someone else on this board who told me that SAM was not appropriate for the configuration I had at 4.1 (3GS, Pwnagtool, ultrasn0w, old bb, AT&T carrier etc.) In any case, I'm happy at 4.0.1 for the time being but know that I'll probably upgrade in the not too distant future. Since the device is jailbroken, I can SSH into it via ftp (fetch).
    Quote Originally Posted by Olethros View Post
    You can "restore from iTunes backup" after you reload the iOS version, however a backup from 4.2 can't be restored on a device running 4.1 (for example). The other way (backup of older iOS version restored onto newer iOS version) works
    Each backup is saved as a folder containing many hundreds of files, you can simply copy this folder and it's contents to make a "backup of your backup"
    iTunes generally only keeps a backup from the last time you synced/backed up your phone.
    Restoring your phone and "setting up as new" will overwrite any previous backups you might have made.

    if you are careful with making "backups of backups" and you stay with the latest iTunes version you can definitely downgrade the OS and restore from the backup that matches your destination OS.
    Great! So "restore from backup" is upward compatible but not downward. This makes sense. Any idea where the backups are stored? I assume they're hidden from the Mac OS but certainly reachable via the Unix shell (btw, I'm fairly comfortable in the Unix shell). This means I could "backup the backup" directory for future use. So the process is: 1) sync the iPhone 2) copy the backup directory to somewhere safe 3) do the upgrade and if I want to return, recopy the backed up directory to the one created just after I synced. 4) option+restore to the previous OS etc...
    Quote Originally Posted by Olethros View Post
    To downgrade, you don't specifically need DFU mode. What you do need is to ensure that iTunes can find your saved SHSH and option-click restore in iTunes, then browse to the appropriate custom IPSW that matches your previous iOS version.
    Once the restore is done, you can select "restore from iTunes backup" and then select the date/time you made a backup for that particular (or older) OS.
    I have all my SHSH blobs safely tucked away in several places including .shsh (thanks to TinyUmbrella). Does each backup that iTunes makes have a unique directory name based on the date/time it was created and then wipes out the n-1th backup or does it have the same name that gets consistently overwritten? I suppose when I figure out where these are, I can experiment to answer this question.

    Quote Originally Posted by Olethros View Post
    Just to be clear, a tiny percentage of people have experienced problems after "restoring from iTunes backup" where the backup was made on a jailbroken/hacktivated phone.
    My personal approach is to "restore from backup" for Y.x.x updates but always set the phone up as new when going to a major new iOS version (eg from 3.x to 4.x).
    Even Apple recommends "set up phone as new" as a valid troubleshooting step if you still experience problems even after a OS restore and a "restore from iTunes backup"
    Good practice.

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    Super Moderator Array Olethros's Avatar

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    Yes, if you are on AT&T and your phone is locked to AT&T (or it's a factory unlocked phone) then you don't need SAM


    The location of the backups is

    windows:
    Code:
    %appdata%\Apple Computer\MobileSync\Backup
    mac:
    Code:
    ~/Library/Application Support/MobileSync/Backup
    See iPhone and iPod touch: About backups for more information.
    Please read the stickies & search forum before posting!
    How to report an iTunes restore/update fail in a useful manner
    -

    iPad 3G 64GB (4.3.3, Redsn0w) oldest SHSH 3.2.2
    iPhone 4 32GB (4.2.1, Redsn0w JB-monte) oldest SHSH 4.1
    iPhone 3GS 32GB (4.3.3; Pwnagetool) factory unlocked oldest SHSH 3.1
    iPhone 8GB (3.1.3; Pwnagetool) AT&T Locked - Unlocked with bootneuter

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    Did we solve your problem? Got a dollar or two spare ? Donate!

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    Quote Originally Posted by Olethros View Post
    See iPhone and iPod touch: About backups for more information.
    VERY helpful! Many thanks.

    Yes, I have a US AT&T model 3GS that is unlocked. Works great with a prepaid SIM from blau.de (in Germany). Yay!


 

 

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