Apple will be releasing iOS 4 tomorrow (or in just a few hours).
Here are some tips to ensure you're ready for the latest iPhone software update as soon as it is released.
Availability and Compatibility:
The multitasking feature will be available only to iPhone 4, iPhone 3GS and the third-generation iPod Touch (32GB and 64GB models from late 2009) users.
The original iPhone or iPhone 2G and first generation iPod touch aren’t compatible with iOS 4.
Update to iTunes 9.2:
iTunes 9.2 that was released by Apple recently is required to download and install iOS 4 so please ensure that you’ve the latest version of iTunes.
Take a Backup of your iPhone:
It is always a good idea to take a backup of your iPhone, iPod Touch before updating it with the latest software update. iTunes will automatically back up your iPhone or iPod Touch when you connect it to your computer. You can also right-click (ctrl key and then click the mouse or touchpad button on a Mac) on your iPhone or iPod Touch under device listing and select Back up from the menu. It might be a time consuming exercise if you haven't backed up your iPhone for a long time. But it's important so don't skip it. You can checkout this post for more details on taking a backup of your iPhone.
Jailbreak iPhone/Unlock iPhone Users:
Though Dev team has confirmed that iOS 4 is unlockable, it would be prudent to wait for them to provide an update on how the latest iOS impacts a jailbroken/unlocked iPhone as you could end up bricking your iPhone.
Taking a Backup Of Jailbreak Apps:
If you’ve jailbroken your iPhone then please note that updating to the latest software update will remove the jailbreak apps. There are couple of apps such as AptBackup (though we haven’t been able to get it to work) and PkgBackup that help you backup jailbreak apps.
However, since iOS 4 is a major iOS update, we would recommend you to reinstall the jailbreak apps that are compatible with iOS 4.
If you have used the Categories jailbreak app then please remove all iPhone apps from folders before upgrading to iOS 4. The apps that are moved to folders using Categories jailbreak app will no longer be visible after the update. So please remember to take care of this one to avoid it. Thanks John for the tip!
After you’ve followed the steps mentioned above, you should be ready to download and install iOS 4 as soon as it is available and start using all the new features in the latest iOS.
If you've any tips based on your experience then please let us know in the comments. If you’ve any questions, please feel free to drop us a line in the comments.
Updated with the tip for Categories jailbreak app.
As recommended by MuscleNerd of iPhone Dev Team, please take a backup of SHSH Blobs (ECID) using Firmware Umbrella. Please note if you have already jailbroken your iPhone, iPod Touch then Cydia would have taken the backup automatically. If you see the message: "This device has SHSHs on file for iPhone OS:" with the version of the current iPhone OS running on your iPhone and iPod Touch then you should be fine and can skip this step. You can checkout our step-by-step guides for Mac and Windows for further details.
We're heard several reports/rumors that iOS 4 should be available at 9:00 or 10:00am PDT.
Getting tired of hitting the 'Check for Update' button? The 9:00 am PDT has passed but still no news of iOS 4 software update. Next one is 10:00 am PDT.