"[iOS 11.3] Battery Health - Replaced Battery?!"に関する回答I have the same problem (unable to determine battery health) but on top of that, my iPhone 6 will also shut down and go into an endless power cycle loop once the battery charge drops to below 20%. iFixit should have given us a warning that their replacement batteries are proprietary and do not comply with Apple's specs (hardware and/or software wise). This really sucks!!!!!!!!!