Upgrading to iOS 4.3.3 on unlocked iPhone 4

[Kobi]

Dear All,
I'm a bit of a novice when it comes to jailbreaking/unlocking. I currently have an unlocked and jailbroken iPhone 4 with iOS 4.0.2 and baseband 01.59.00. It has been suggested that I upgrade to iOS 4.3.3 to help fix an issue with my 3G connection.
Firstly, what would be the best way to do this and secondly, would I then need to unlock the phone again (and what would be the best way to do this)?
I am currently living in Ethiopia so have to have the phone unlocked and currently I'm without a 3G connection so if there is any way I could do all this on my PC (i.e. not using Safari on my phone) that would be better. If necessary I can get a wi-fi connection though.
Sorry for rambling a bit and I hope it makes sense.
I'd be eternally grateful for any help anyone can offer.
Thanks

Kobi

 

[bab2010]

There is a new iOS which is going to be release soon, i would suggest you to wait for that iOS before upgrading, but if it's a concern and you want to upgrade to the 4.3.3 then just plug in your iphone to your computer and upgrade it using itunes on your computer. You will beed a very good internet connection for itunes to download the iOS, after that, get redsnow jailbreaking tool and iOS 4.3.3 gsm from internet and jailbreak your device. Your baseband is supported by ultrasnow, so once the jailbreak is done, you can just head to cydia and get ultrasnow from cydia and unlock your device. Good luck incase you decide to upgrade.

 

[Kobi]

Thanks very much for the advice. I was previously told that if I upgraded through iTunes that I would also change the baseband and that that might mean I would then be unable to unlcok it again, is that the case. To be quite honest I am more inclined to listen tou your advice as I'm sure you have much more experience that people do here! Many thanks again
Kobi

 

[bab2010]

Thanks very much for the advice. I was previously told that if I upgraded through iTunes that I would also change the baseband and that that might mean I would then be unable to unlcok it again, is that the case. To be quite honest I am more inclined to listen tou your advice as I'm sure you have much more experience that people do here! Many thanks again
Kobi

Yep if you are actually jailbreaked and have changed your baseband, upgrading the iOS via iTunes will restore back the original baseband. You will then have to manually change your baseband again in order to unlock. What you can do right away is to manually download the ipsw you want from Internet, cook it with pwnage or snowbreeze tools and upload it to your iPhone via iTunes using the "shift + restore" key that way, you can keep your baseband while having your iOS upgrade.

 

[iphone4Cig]

But I was reading u post and I thought the iPhone 4 baseband can't be changed only the 3G & 3GS..if I'm right u will have to use snowbreeze to save your baseband with a custom ipsw to update your iPhone 4

 

[bab2010]

But I was reading u post and I thought the iPhone 4 baseband can't be changed only the 3G & 3GS..if I'm right u will have to use snowbreeze to save your baseband with a custom ipsw to update your iPhone 4

the iPhone 4 baseband can be change for sure. What I don't know is if it's possible to change a factory unlocked iPhone baseband. And if yes, why will one want to change the factory unlock baseband of the iPhone 4?

 

[iphone4Cig]

So this phone is factory unlocked just update through iTunes but that thought is was just software unlocked?

 

[f4780y]

So this phone is factory unlocked just update through iTunes but that thought is was just software unlocked?

It is possible to purchase factory unlocked iPhones. bab2010 has one of those. The baseband in these phones is still updated, just like everyone else's, however the phone will always remain unlocked no matter what.
The key which unlocks the phone permanently is stored in a part of the phone which never gets updated by a firmware or baseband restore. This is a common design across all mobile phones, not just the Apple iPhone.

Phones which are sold under contract are locked. It is possible to unlock them "officially" just like any other type of phone on sale today. To do this you must get an unlock code from the carrier you are locked to. Once that code has been applied to the phone, it will act just like any other factory unlocked phone. It will be permanently unlocked for the rest of it's life, no matter what updates or restores you do.

Finally, if you phone remains carrier locked, the only other way to unlock it is with a jailbreak and software unlock such as ultrasn0w, or a hardware solution such as the gevey SIM (which may be illegal in your country).

As bab2010 pointed out correctly, you can never downgrade the baseband on an iPhone4 to an earlier version. All you can do is try and preserve the baseband you have using TinyUmbrella, or a custom firmware such as pwnage / sn0wbreeze as was mentioned. So to be clear, even with these tools, you cannot roll a baseband back to a version less than it currently is. You can only preserve it.

 

[flamingo157]

I am facing a similar problem - I want to upgrade my iPhone from 4.0 to 4.3 OS. I did jailbreaking and unlocked at the time of purchase from a local store in UK but have lost original O2 sim.

1. Is it possible to just upgrade jealbreak OS to 4.3 without iphone4 getting locked again? As I assume I need original O2 sim to unlock n jealbreak to higher versions.

2. Does it gives guaranty that my iPhone4 remains unlocked doing just jealbreak up-gradation?