iPhone jailbreak/unlock from 3.1.2 to 4.x

September 27, 2010 7:44 AM

What is the best way to upgrade a jailbroken+unlocked iPhone 3GS from 3.1.2 to 4.x? (details inside)

Technical specs:
- iPhone 3GS
- iOS 3.1.2 (7D11), new bootrom
- jailbroken with redSn0w 0.9.2 (requiring a tethered boot)
- unlocked with blacksn0w RC1
- SHSH's on Cydia for 3.1.2, 3.1.3, 4.0, 4.0.1, 4.0.2

The goal would be to
- upgrade to a 4.x version of iOS
- jailbreak it without the need for a tethered boot
- unlock it

Alternatively, if that's not possible, is there a way to
- stay on 3.1.2
- and lose the tethered boot
- without giving up the unlock?

posted by lord_yo to Technology (4 answers total)

Response by poster: oops, I forgot the baseband info: it's 05.11.07
posted by lord_yo at 7:47 AM on September 27, 2010

Why not restore from a 4.x ipsw file (gives you a "clean install" version of the iPhone).
Jailbreak again
Unlock again

I mean, there's nothing in those steps that you haven't already done with the phone, so therefore nothing in it should be new/difficult to you, especially given the plethora of sites detailing how to do both of the above.
posted by Biru at 8:23 AM on September 27, 2010

FIRST THING: save you SHSH blobs! This will let you downgrade to your current OS if you upgrade but can't jailbreak.

I think if you upgrade to iOS 4.0.1 you can use jailbreakme to jailbreak. Then you're probably best off staying on 4.0.1 for now (but install a fix for the Safari PDF exploit). That said, I'm not sure if the SHSH blobs you saved would let you restore to iOS 4.0.1 (I'm not sure if SHSH blobs are version-specific or just need to exist for the phone).

I don't think 4.1 is currently jailbreakable for 3GS new bootrom. It is jailbreakable for the old bootrom as long as you start with an already jailbroken phone though.
posted by Emanuel at 10:01 AM on September 27, 2010 [1 favorite]

Best answer: I'm posting while sleepy-- does this do the trick for you?
posted by kimota at 8:05 PM on September 27, 2010