How To Install Ios 8 On Iphone 4s

Today's the day: iOS 9 makes its debut, and maybe you're one of the many users who are excited to upgrade your iOS device. I'll cover how to upgrade to iOS 9 and how to do a fresh install of iOS 9 in this article. (If you're wondering if you should upgrade in the first place, we think you should.)

But then, if, for whatever reason, you decide you need to downgrade back to iOS 8, I'll also show you how it's done. Keep this in mind: The window to revert back is small. Apple will eventually stop authorizing iOS 8, and when that happens and you have iOS 9 installed, there's no going back.

If you're very concerned about your apps not working or your device not performing up to par, don't upgrade to iOS 9 immediately. You'd be better off waiting for Apple to release the first major update to iOS 9, which may address some of the bugs you are afraid of running into, and it also gives developers time to update their apps.

Is your device compatible?

Apple says that iOS 9 is compatible with the following devices:

iPhone

iPhone 4s
iPhone 5, iPhone 5c, iPhone 5s
iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus

iPad

iPad 2, iPad third generation, iPad fourth generation
iPad Air, iPad Air 2
iPad Pro
iPad mini, iPad mini 2, iPad mini 3, iPad mini 4

iPod touch

iPod touch fifth generation, iPod touch sixth generation

Some features in iOS 9 may not work on older devices in the list above. If you're an owner of a device that's on the older side of the compatibility list, consider putting off the upgrade to iOS 9 until you get more information on how the new iOS performs on your device.

Back that device up

Before you upgrade to iOS 9 (and, when iOS 9 is installed, before you install any iOS updates), you need to back up the data on your device. You can back up via iTunes on your Mac (fastest) or back up to iCloud (more convenient).

We have complete instructions on how to back up your iOS device in iTunes 12 or via iCloud. (The linked article is about preparing for iOS 9, but it includes backup instructions.)

Upgrade to iOS 9

OK, it's time to install the new iOS. You have two ways to install iOS 9: Directly on your device using a wireless connection, or through iTunes with your device connected to your Mac. If you want to install directly, you need several free gigabytes of storage space available. If you don' have to room, use iTunes on your Mac.

Install iOS 9 directly

Make sure you have a good amount of battery life left. Anything above 60 percent should be fine, but the weaker your wireless connection, the more taxing the connection will be on your battery. Plug in your device, if needed.
Tap the Settings app on your iOS device.
Tap General.
You'll probably see that Software Update has a badge. Tap Software Update. If it doesn't have a badge, tap it anyway; this will trigger the phone to check to see if an update is available.

A screen appears, telling you that iOS 9 is available to install. Tap the Install button. The download and installation will take a few minutes.

Install iOS 9 though iTunes on your Mac

Connect your iOS device to your Mac using the sync cable and then launch iTunes.
If iTunes already knows that the update is available, an alert will pop up, asking if you want to update your device. Click the Download and Update button to install iOS 9 right away. If you want to download the update but install it later, click Download.

If you don't see an alert, click on the device icon in the upper left and then click on the Summary tab in the left column. In the right window, click on the Check for Update button. If it's available, the version of iOS 9 for your device will download to your computer for installation.

Next page: Perform a fresh install of iOS 9

Perform a fresh install of iOS 9

A new iOS can also mean a fresh new start. Maybe you've installed too many apps on your iOS device, and you want to use this opportunity to start from scratch and install only the apps you really want. Whatever the reason, you can wipe out your device and then install iOS 9.

This is done by restoring your iOS device using iTunes. It takes more time than just upgrading the already-installed operating system, and that doesn't include the time it takes to reinstall your apps. Here's how to restore and then install iOS 9 on your device.

Connect your iOS device to your Mac using the sync cable and then launch iTunes.
Click on the device icon in the upper left and then click on the Summary tab in the left column.
In the right window, click on the Restore iPhone button. You'll be asked if you want to back up your device; if you haven't backed up in a while, it's a good idea to do so. Be sure to confirm that you want purchases made on your device copied over to your Mac.
A confirmation dialog appears. If you're sure you want to restore, click the Restore button.
iTunes will restore your device using iOS 9. This will take a while.
When the process is done, iTunes will ask if you want to set up as a new device, or restore from a backup.

If you restore as a new device, you'll have to enter settings for Wi-Fi, your Apple ID, Siri, and more. You can then use iTunes to determine what apps to install on your device.

If you want to restore from a backup, you'll be asked to select a backup file that iTunes will use to restore your device.

Next page: How revert back to iOS 8

How to revert back to iOS 8

You installed iOS 9. Whoo-hoo! But then you noticed that your device is behaving badly. Boo! You want to revert back to iOS 8.

If that's what you want to do, don't hesitate. Apple "signs" each version of iOS, which is a way of approving the software for each device. When a new version is released, the previous version remains signed for a short period of time, and then Apple stops signing the previous version. This means you can't go back to the old version. (If you waited, say, a week after iOS 9 was released, there's a good possibility that Apple stopped signing iOS 8 and you can't go back.)

Find the .ipsw file

To see if you can revert back to iOS 8, look for the .ipsw file on your Mac. Here's how to find it.

In the Finder, hold down the Option key and select Go > Library. (The Library folder is usually invisible in your Home folder. If you don't hold down the Option key, the Library selection will not be available.)
Open the iTunes folder.
You may see an iPhone/iPad/iPod Software Updates folder. Open it.

You should see a file called "[yourdevice]_8.4.1_[firmwarenumber]_Restore.ipsw" or something similar. This is the file that will allow you to revert back to iOS 8.
Drag that file to the Desktop.

If you don't see a file, you can try searching the Internet for ipsw download. There are a few websites that have old software available.

Install iOS 8

Once you acknowledge that you have the ipsw file, here's how to revert back to iOS 8.

Connect your iOS device to your Mac using the sync cable and then launch iTunes.
Click on the device icon in the upper left and then click on the Summary tab in the left column.
In the right window, click on the Restore iPhone button while holding down the Option key.
A navigation window will appear. Navigate to the .ipsw file on your Desktop, select it, and click Open.

A confirmation dialog will appear. Click the Restore button.

iTunes will perform a restoration of your iOS device, and in a few minutes, iOS 8 will be up and running.

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Operating Systems
iOS
iOS 9

Roman has covered technology since the early 1990s. His career started at MacUser, and he's worked for MacAddict, Mac|Life, and TechTV.