https://blog.wongcw.com/2021/05/11/iphone-11-12%e5%8d%87%e7%b4%9aios14-5-1-%e6%80%a7%e8%83%bd%e5%8d%bb%e9%80%80%e5%9b%9e3%e5%b9%b4%e5%89%8d%ef%bc%9f/
iPhone 11/12升級iOS14.5.1 性能卻退回3年前?