15.4 won't install on Iphone 12, ipad, or ipod

IOS 15.4 extracts software, prepares update then fails to install on all three devices for "unknown error."

I have itunes and windows current. My wifi and ethernet connection are fine.


Why would it fail on all of them, and how can i install the upstes?

Posted on Mar 23, 2022 12:25 PM

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Question marked as Top-ranking reply

Posted on Mar 23, 2022 12:35 PM

To update over the air from the phone all of these requirements must be met:

  • You need at least 6 GB of free storage
  • You must be connected to a Wi-Fi network (and not a personal hotspot) unless it is an iPhone 12 or 13 series with an active 5G network connection
  • The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
  • The phone must not be in Low Power Mode
  • The phone must not be connected through VPN
  • The phone cannot be in Airplane mode
  • You cannot still have a beta version installed on the phone


If you can't meet all of them you can still update using your computer.


The above is the short answer. Here is the long answer→Updating iOS: common issues and solutions - Apple Community

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15.4 won't install on Iphone 12, ipad, or ipod

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