This is a nice addition to the promised unlock, and despite yellowsn0w being labeled as 0.9.1 and a beta, reports are coming in of numerous successful unlockings. Of course, there are issues as well, so read through the comments before performing your own unlock, to decide if you want to do so.
- You need to install the latest 2.2 firmware (downloaded from here).
- Jailbreak your iPhone, using QuickPWN 2.2. Those using MacOS 10.5.6 need to re-enable DFU mode, which Apple disabled as a way to prevent Mac owners from jailbreaking their iPhones.
- You can install yellowsn0w 3G unlock by using either Cydia or Installer, add the yellowsn0w repository addresses posted on the iPhone Dev Team site to your installer application (iPhone Dev Team has requested no direct linking, possibly because they may change the location).
If you use T-Mobile in the U.S., remember to turn off 3G.
There's no PIN support yet. They are still working out the flow for SIMs with PINs enabled. You have to disable any PIN you may have on a SIM before trying yellowsn0w, for now.
The DevTeam also says that once you are done installing yellowsn0w through Cydia:
- Return to the main Cydia menu
- Restart your iPhone with the 3rd party SIM installed
- Wait for the slide to unlock screen, and then wait 10-15 seconds.
- If you don't see your carrier name appear, you must remove your SIM, insert it again, and wait 10 seconds. (The DevTeam plans on eliminating this step)