I am running 3.1.3 on a jailbroken 3G with T-Mobile service. I am happy with the 3.1.3 but want to use the QIK app which now requires an upgrade to 4.0+.

Can I upgrade without losing all my saved apps?

Originally Posted by lgsr1

I am running 3.1.3 on a jailbroken 3G with T-Mobile service. I am happy with the 3.1.3 but want to use the QIK app which now requires an upgrade to 4.0+.

Can I upgrade without losing all my saved apps?

Moved to a separate thread as you were clearly threadjacking.

Okay there are three points to consider here.

1. 4.x includes a soft-SHSH for the 3G iPhones, so any restore or update needs to be signed and approved by Apple. Now that iOS 4.1 has been released, Apple no longer signs/approves restore requests for 4.0, 4.0.1 or 4.0.2 (did you get your soft-shsh via Cydia for any iOS 4.0.x version?)
2. iOS 4.1 has not yet been jailbroken for the 3G (will not take long for a jailbreak to be released).
3. 4.1 also includes a baseband update that breaks ultrasn0w. There are no plans to make ultrasn0w work with the new baseband.

These three points affect all iPhones with IOS 4.1

You can use custom IPSW (pwnagetool) to go to ios4.0, that will bypass the SHSH check mentioned earlier.

The performance on the 3G running 4.0 is particularly bad, this has been significantly improved in 4.1

My advice is to wait for pwnagetool to be released for 4.1 / 3G, you need custom IPSW to stop your baseband being updated (as you are on t-mobile USA you rely on unlock). Also the performance is better with 4.1

Also to answer your specific question: upgrading is possible, but you will lose unlock (and need to rejailbreak).
What I recommend is to:

1. Sync with iTunes, confirm that this also updates the backup of your iPhone
2. Restore with pwnagetool custom IPSW (save unlock and jailbreak)
3. Restore your apps and settings from iTunes backup.

That works fine for most people, however some experience instability or poor battery life due to "old/junk settings" that are restored from your previous backup. Mostly a "reset network settings" fixes this.

Hello... OK first of all i'm new to this. I've looked everywhere but most of the stuff i find is outdated and I feel as i'm very behind lol....
here is my problem...

I have just got an iphone 3gS with 3.1.3 and firmware is 05.11.07... I have jailbroken it with jailbreakme and unlocked with ultrasn0w.

Now I want/need to upgrade to atleast 4.0 so i can use the multitasking feature and other apps.
Plus I'm not using ATT and would like to ugrade to something in which i can use any carrier...

I've read about shsh blobs and custom ipsw over and over again but just dont understand it. :-(

Can anyone please help me out? Please post any links you might have also.
THANK YOU.

Originally Posted by UltraSpy

Hello... OK first of all i'm new to this. I've looked everywhere but most of the stuff i find is outdated and I feel as i'm very behind lol....
here is my problem...

I have just got an iphone 3gS with 3.1.3 and firmware is 05.11.07... I have jailbroken it with jailbreakme and unlocked with ultrasn0w.

Now I want/need to upgrade to atleast 4.0 so i can use the multitasking feature and other apps.
Plus I'm not using ATT and would like to ugrade to something in which i can use any carrier...

I've read about shsh blobs and custom ipsw over and over again but just dont understand it. :-(

Can anyone please help me out? Please post any links you might have also.
THANK YOU.

You are threadjacking an unrelated thread. Please try to understand that advice for one model (say an iPhone 3G) may not be correct for another model (3GS, 2G, Iphone 4) etc.

I'm not going to answer your questions in this thread (as that will just exacerbate the threadjacking) but my suggestion is you keep on reading about SHSH until you DO understand it! Then if you still have questions, ask in a thread that specifically relates to the problem you have.