I had trouble downloading iOS Public Beta 3 on my iPhone 5. iOS kept telling me that installation had failed because there was an error downloading the software. Restarting my phone did not help. Here’s what I did to get it working:
- I removed the Beta Program profile from Settings.app > General > Profiles
- Restarted my phone
- Re-enrolled my device at http://beta.apple.com/
- Rebooted my phone when prompted
- Powered my phone off afterward, and powered it back on
- Checked for updates again in Settings.app.
This time, the updated downloaded correctly. It’s installing now.