Updating jailbroken 3GS 4.1 to 4.2.1?

[loungelizard]

Can somebody tell me what would be the best way to upgrade my iPhone 3GS in the following scenario? ...

My iPhone 3GS has currently iOS 4.0.1 installed and was jailbroken with the jailbreakme.com exploit that appeared for a while after iOS 4 came live. I have the 4.0.1 SHSH blobs on Cydia as well as on my harddisk.

Now I want to upgrade to the latest iOS 4.2.1 but stay jailbroken after that. Is it possible with any of the JB tools available?

An important note here is that for some reason iTunes doesn't do a full backup of my phone anymore and there seems to be no option in iTunes 10 to enable/disable this (as it was with iTunes 9 I remember). So iTunes only syncs my apps now whenever I connect but never backs up all the custom data. For this reason I don't want to do a full iPhone restore if possible (unless somebody knows who I can get iTunes to backup my stuff fully).

[Orby]

Can somebody tell me what would be the best way to upgrade my iPhone 3GS in the following scenario? ...

My iPhone 3GS has currently iOS 4.0.1 installed and was jailbroken with the jailbreakme.com exploit that appeared for a while after iOS 4 came live. I have the 4.0.1 SHSH blobs on Cydia as well as on my harddisk.

Now I want to upgrade to the latest iOS 4.2.1 but stay jailbroken after that. Is it possible with any of the JB tools available?

An important note here is that for some reason iTunes doesn't do a full backup of my phone anymore and there seems to be no option in iTunes 10 to enable/disable this (as it was with iTunes 9 I remember). So iTunes only syncs my apps now whenever I connect but never backs up all the custom data. For this reason I don't want to do a full iPhone restore if possible (unless somebody knows who I can get iTunes to backup my stuff fully).

You can restore/upgrade to 4.2.1 and jailbreak again, but unless you have an old-bootrom 3GS, your jailbreak will be tethered. 4.1 is probably a better choice because of Cydia app compatibility and untethered-ness (and much easier to unlock if you need an unlock).

For 4.2.1, I'm pretty you have to upgrade or restore to a stock IPSW and then use redsn0w to jailbreak from there. 4.1, a custom IPSW can jailbreak you out of the gate.

As for the iTunes thing, I'm assuming you tried right-clicking the iPhone, and selecting "back up." If that doesn't do it, I don't know what would (I am not an iTunes-malady expert, sorry!).

EDIT: To clarify your main question a little better: while you can restore to an already-jailbroken IPSW using PwnageTool... SEE EDIT2.

EDIT2: You actually might be able to upgrade to 4.2.1 stock (won't wipe your content) and use redsn0w from there... I would not recommend that route however, as it's rather risky and not tested very well (if at all).

[loungelizard]

Thanks for clarifying this orbyorb!

I'd like the 4.2.1 if possible since there are some apps that require it. I'm wondering if I can safely upgrade to 4.2.1 via iTunes without bricking my phone (which means iTunes will do it's iOS update business over my JB'd phone)?

As far as I understand the phone will be un-jailbroken again after such an update. But after that I could try and see if I can JB with redSn0w (or at a later time when there's a tool and it's safe that a JB works? I wouldn't mind if my phone is not jailbroken for a short while but I'd like to make sure that it's possible to JB in the future).

Ok, I checked my phone's serial number and according to redsn0w it has the old boot ROM (week 24). Now the big question for me is: if I apply a new (stock) iOS 4.2.1 ROM via redsn0w, does it wipe any user data from my phone (since this PoS named iTunes doesn't let me backup anything)?

UPDATE: Oh well, so I went ahead and updated ... update to iOS 4.2.1 via iTunes, no problem. After that I used redsn0w to jailbreak, exactly as written here: iClarified - iPhone - How to Jailbreak and Unlock Your iPhone 3GS Using RedSn0w (Windows) [4.2.1] but without restoring the whole phone.

Now my phone hangs in boot loop!

[Simon]

You need to know for sure what bootrom you have. Download idetector to find out.

[loungelizard]

You need to know for sure what bootrom you have. Download idetector to find out.

Would be good if I had known this tool before I used redsn0w~! Now it seems the only way to repair is to restore and I have no backup of the user data.

Well iDetector says my bootrom is the old one so at least in that point everything went right.

EDIT: So question now is: Is restoring the only way or is there a chance to get my data backed up somehow (via iPhoneBrowser or whatever)?

[Simon]

If you dont have a backup and your phone is stuck in boot loop then you may be out of luck. When you ran redsnow did you say no to the question about if you have the new model 3GS?

[loungelizard]

If you dont have a backup and your phone is stuck in boot loop then you may be out of luck. When you ran redsnow did you say no to the question about if you have the new model 3GS?

Yup, that's what I did. Only custom thing I did was to check verbose boot mode.

[Simon]

Thats what may have messed it up. best to keep it to the basics. Try running redsnow again just choosing cydia.

[loungelizard]

Restored now. After that JB'ed with redsn0w with all settings as default and all worked flawless!

I just hate Apple so dearly much for this PoS called iTunes which fails to do any backups and which generally is an embarrassment of an application!

If I had a two year old daughter, she could code a better application than iTunes, using wood blocks!

[Simon]

It seems weird that a backup is not done for you. Mine does backups.

[loungelizard]

It seems weird that a backup is not done for you. Mine does backups.

Yes, I don't even have an option to select 'backup' if I r-click on my iPhone name. There's ony 'sync' which only syncs the apps. I tried setting a backup password and after that iTunes was approaching an automatic backup but then failed with some lame error message (cannot backup because of an unknown error ...).

[Simon]

Have you tried it on a different computer to see if the backup option is there?

[loungelizard]

Nope but I uninstalled iTunes now, wiped all traces of it from my harddisk and re-installed and now backup works again.

[Simon]

Good to hear