iPhone 3GS, iOS 5.1, old bootrom jailbreak

[jdcnosse]

So, little bit about me. Big Android fan lol but iPhone isn't too bad either. Been a member of xda for awhile, and then found this place. I know my way around a computer for the most part.

Anyways, I got this phone off craigslist. When I bought the 3GS it was at 5.1 already with baseband 05.16.05 (or 05.15.05 lol). I've used two methods to jailbreak the phone, redsn0w and sn0wbreeze. I only have at the moment 4.1 and 5.1 SHSH blobs, but I read somewhere that within custom IPSWs, you don't need those...am I correct? Right now it is jailbroken via Sn0wbreeze, but it doesn't get stuck at the apple/snowflake when booting, so that means its interbreeding right? Thanks to sn0wbreeze, I did find out I'm a lucky bum with the old bootrom.

I also wanted to unlock it, but was told the only way to do that on my current baseband would be to downgrade to iOS 4.1 and then install the iPad baseband (06.15.00) and then use ultrasn0w. A question...can I upgrade from this to say iOS 5.0.1 (without SHSH blobs) or 5.1 (with/without blobs)?

Also, I don't actually have a regular AT&T SIM card. The closest thing I have is an AT&T GoPhone SIM, which I've been told will work sometimes, as long as the SIM isn't locked to the phone it came with. It is an orange and white SIM with the GoPhone logo/label on it, which I've heard are locked down temporarily. I also expect to get a prepaid T-Mobile SIM in the next week. When I tried using ultrasn0w just now on my iPhone 3gs with jailbroken iOS 5.1, it didn't give me an error message, just displayed "No Service" where it would normally say AT&T. Funny thing is a lot of the time, the GoPhone SIM will bring up an "Invalid SIM" or "SIM Failure" message.

Sorry for such a long post, I just want to know what is the best way to get this working so that I can sell it to my buddy. So mostly jailbreaking and unlocking, if those are possible at all.

Thank you in advance for all your help.

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[J03Y4G]

You can upgrade all you want, I'm not sure having an old bootrom really let's you downgrade to whatever iOS you'd like, from what I've remembered it was to be untethered on any iOS, if you want to unlock install the iPad baseband cuz I don't think downgrading will also downgrade your baseband unless you just want to try.

iPad baseband can be installed via redsn0w.

[jdcnosse]

I didn't think having an old bootrom meant I could downgrade to any iOS, I downgraded to 4.1 because Apple is still signing that apparently. I already have the iPad baseband installed, just need to make sure that ultrasn0w is actually working...

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[J03Y4G]

Yes ultrasn0w works with the iPad baseband on iOS 4.1

[jdcnosse]

Sorry, I must have not made myself clear but I know that as well, that is how I originally flashed the iPad baseband.

I'm just looking for some suggestions on the easiest method to get untethered jailbreak and unlock on the iPhone 3GS.

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[J03Y4G]

Just jailbreak and install ultrasn0w through cydia n it done that easy 4.1 is untethered

[jdcnosse]

Alright thanks. If I jailbreak via 4.1, and later decide to upgrade, I have to use a custom IPSW to preseve the iPad baseband correct?

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[J03Y4G]

Once you have the iPad baseband it is not reversible, you will always need custom ipsw

[jdcnosse]

That's what I thought, just making sure. What would happen if I restored a stock IPSW? I mean I know the iPad baseband is irreversible but would I need to reflash the BB?

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[J03Y4G]

No way to reflash it if you want a clean iOS just use redsn0w to make a custom ipsw it will never be pre-jailbroken but your will still have the iPad baseband.