A&A said:
Do you mean "jailbreaking"? Can you "unlock" without "jailbreaking"?
You have to
jailbreak it first, and then
unlock it. Here's what each means:
jailbreaking - allow the iPhone to run non-Apple approved apps.
unlock - allow the iPhone to use other carrier's SIM cards
Some technical details:
When Apple released the iPhone OS 3.1.3 in February, they upgraded the baseband firmware of the device as well. This basically broke all the previous methods of
jailbreaking and
unlocking the phone. The hackers figured out how to
jailbreak it again and released a way to do that. (See
http://spiritjb.com/ for an easy jailbreak tool.)
They also figured out how to
unlock it, but they did not release that to the public. They decided to keep it to themselves until Apple released the newest iPhone 4. This way, Apple would not be able to fix the problem before releasing the new iPhone (which would have caused the hackers to start from the beginning again). Now that the new iPhone is being released on June 23 in the States, expect to see a
unlock coming shortly afterwards.
Please note that once you
jailbreak and
unlock your iPhone, you can never use the Apple upgrade through iTunes again. You have to wait for hackers to release a new version of their hack. Usually not a big deal but you may end up waiting for new features a bit.