The ‘baseband’ is the generic nickname given to the internal components of the iPhone that handle the phone calls and Internet access. This ‘baseband’ is a tiny and unique independent computer system that runs inside your iPhone, it is separate to the main system that handles the applications (such as email and google maps) and it talks to the main part of the phone over an internal communications network.
Think of it like a cable modem or other peripheral that is attached to your home PC that needs occasional updates. When a software update is released and presented to you within iTunes the baseband is sometimes updated (to fix bugs or add new features).
The 3.1 update for the iPhone 3G and 3GS contains such an update, so running the vanilla updater straight away with iTunes will reprogram and update the baseband.
WHICH DEVICE DO I HAVE?
Read the description to identify your device, once you have correctly identified your device follow the specific instructions for that device as listed below.
SIM Free/SP Unlocked/Factory Unlocked iPhone 3G(S)
This applies if you bought your iPhone 3G(S) for $$$$$$$. This model of iPhone 3G(S) doesn’t have an Service Provider lock (aka factory unlocked) and you are able to put any SIM card into the phone and get service. Your phone is already unlocked so you do not need to worry about baseband updates, if your device was Pwned at 3.0 or 3.0.1 then you can use PwnageTool to create an ipsw and then use this to update and jailbreak your phone.
SIM Free/SP Unlocked/Factory Unlocked iPhone 3G
This applies if you bought your iPhone 3G for $$$$$$$. This model of iPhone 3G doesn’t have an Service Provider lock (aka factory unlocked) and you are able to put any SIM card into the phone and get service. Your phone is already unlocked so you do not need to worry about baseband updates, if your device was Pwned at 3.0 or 3.0.1 then you can use PwnageTool to create a 3.1.ipsw and then use this to with iTunes to upgrade and jailbreak your phone.
iPhone 2G (1st Generation)
Use PwnageTool to do the magic and then restore with iTunes using your newly created .ipsw ‘nuff said, you don’t need to worry about anything, the baseband will be unlocked, the phone jailbroken.
iPod Touch 1G (Original iPod Touch)
Use PwnageTool to create a firmware image and restore with that .ipsw using iTunes.
iPod Touch 2G
Use PwnageTool to create a firmware image and restore with that .ipsw using iTunes, this will only work if you are already Pwned at 3.0 or 3.1.
iPod Touch 3G
At this time PwnageTool does not support this device.
Official Bittorrent Releases -
The following links are unofficial download mirrors, you download these at your own risk, we accept no responsibility if your computer explodes or if it becomes part of a NASA attacking botnet or even worse if your hands fall off mid-way during the use of these files. We do not check these links or archives and we accept no responsibility with regard to the validity of the files, or with other content these links provide or with the content that is on the linked site. Always check the published SHA1 sums. We would prefer that you downloaded the official bittorrent release that is linked above, but you are welcome to try these if you really must. Mirror owners should email direct links only to blog@iphone-dev.org , please don’t place mirrors in the comments as they will be deleted.
For updates visit http://blog.iphone-dev.org/