Help! Unlocked iPhone 3GS needs updated!

[Tabatham]

I purchased an already unlocked iPhone 3GS from a website. They told me that the phone was updated to iOS 5.1.1 but it is not. It is only on version 4.1 and because of this I cannot download apps or even look at Facebook without it overloading and shutting down safari. Can someone please help me by explaining very simply step by step any way that I can update this phone to a newer iOS without messing with the unlock? The phone has a cydia app on the main page, but I truly know very little about what to do with it. I am on firmware 05.12.01

[RochOAR]

If it isn't already, get it factory unlocked. Search ebay. I've done 2 of them and paid $5 each. Just check the reviews. After that you can upgrade to any iOS.

[Tabatham]

I live in New Zealand, the phone came from a random possibly Asian website and it came to me Unlocked but not factory unlocked, I am pretty sure I can't get it factory unlocked.

[King_O_Hill]

If it isn't already, get it factory unlocked. Search ebay. I've done 2 of them and paid $5 each. Just check the reviews. After that you can upgrade to any iOS.

What does being factory unlocked have to do with jailbreaking????

You need to have the blobs for that firmware. When you open the Cydia app, just above the words "Welcome to Cydia", it will show "SHSH iOS...", the numbers following are the iOS numbers that Cydia saved the blobs for. If 5.1.1 is in that list, you may be in luck to get it to that firmware.