Here’s a written guide that will show you how to install iOS 8.4 beta 4 for free without the a developers account or registered UDID. This is nothing new and is very simple whether you’re running a Mac or Windows computer.
Before You Start
Note: As always backup all of your content and settings in the cloud, or on iTunes. Tap “Check For Update” not “Restore iPhone” (you cannot restore your device to iOS 8.4 beta 4, only update.) Make sure to download the correct IPSW matching your device. Check your model number on the back of your device.
Once you have everything in order you can download iOS 8.4 beta 4 here.
Step 1. Download all necessary IPSW files. (If you get an error and you’re sure you downloaded the correct IPSW, download it again; It happened to me.)
Step 2. Connect your device and launch iTunes.
Step 3. Hold “Option” if you’re on a Mac, or the “Shift” Key if you’re on a Windows PC, and left click the “Check for Update” button in iTunes.
Step 4. Search for and select your iOS 8.4 beta 4 IPSW you downloaded earlier, and tap “Open.”
Step 5. Allow 10-15 minutes for install. Presto! you are now enjoying the latest iOS 8.4 beta 4 release on your device!