A series of faulty iPhones do not accept SIM, cannot connect to Wi-Fi, data after upgrading to iOS 12.1.4

Last week, Apple officially released iOS 12.1.4 to patch a serious security hole on the FaceTime application, allowing callers to hear sounds from recipients even if they did not start the phone. However, after upgrading to this update, many iPhones have failed to connect to wifi network or 4G, even without receiving sim.

Previously, when iPhone running iOS 12.1.2 and iOS 12.1.3 also had the same problem, not making calls or connecting wifi and mobile network turned smartphone into 'brick'.

On Apple Support appears many reflections of users on this issue.

An account complains about iPhone not accepting SIM after upgrading to iOS 12.1.4.

Another account says your iPhone cannot connect to wifi.Or even, there are faulty users who cannot use both data and Wifi.

Notice of smartphone cannot receive sim.

Apple's @AppleSupport account gave feedback under a few tweets, but most were directed to its support page, not giving a specific fix.

Hopefully, Apple will really fix these serious bugs in the next update, and of course not adding new bugs.