That’s right. Unless you got a factory unlocked iPhone 4, which is available almost everywhere except the US right now, you wouldn’t be able to carrier unlock your iPhone 4 for some time to come. While iOS 4 on iPhone 3G and iPhone 3GS has already been unlocked with ultrasn0w 0.93, the baseband OS in iPhone 4 is completely different.
iPhone 3G and 3GS have a different baseband CPU than the iPhone 4 hence running different OS as well.
The iPhone 3G and 3G[S] both ran Nucleus OS on thePMB8878 baseband CPU (aka XGold 608), where the iPhone 2G ran the PMB8876 (aka S-Gold 2). iPhone 4 uses the PMB9800, or X-Gold 618 – running a separate OS – ThreadX, an RTOS by ExpressLogic.
Before the unlock, the iPhone 4 needs to be jailbroken as well. Once that’s been done, the work on an unlock will start. Don’t keep your hopes up on getting a locked iPhone 4 and using it with another carrier anytime soon. A safe bet would be to get a factory unlocked version.
Of course, we’ll keep you updated on any progress on this. Stay tuned! [via ModMyi]