As promised, the iPhone Dev Team released an unlocking software for the iPhone 3G on the first day of the new year. The software, dubbed "Yellowsn0w," requires the user to have a jailbroken iPhone with a baseband of 02.28.00, which is provided in the latest 2.2 firmware from Apple.
Yellowsn0w works by launching a payload injector during the boot, or when the baseband is reset. It's describe as a "small program" that's unobtrusive, and the end user won't notice anything other than the third-party SIM card working. The Dev Team said the software can be easily removed and the software makes no permanent changes to the handset.
"The iPhone 3G is used all over the world with all sorts of SIM cards, and we almost certainly will see untested and unexpected situations," the Dev Team wrote on its blog. "If the soft unlock doesn't work for you on day 1 (literally day 1, of 2009!) then please don't panic or be impatient. This is new territory for everyone, so enjoy the ride as much as you can."
In the United States, the unlock means iPhone 3G users can use wireless services from GSM providers other than AT&T. But the touch-screen smartphone still uses 3G frequencies that are unique to AT&T, so unlocked iPhones using T-Mobile's voice network would only be able to access the slower EDGE data service.
The unlock may have more appeal for globe-trotters because voice and data networks are more standardized in other countries. For example, an unlocked iPhone 3G owner could forgo international roaming rates when traveling by popping in a local SIM card.
But the unlocking software carries some risks, as it voids the warranty and Apple could potentially disable the device with a software update.