Touch ID

Touch ID is a security feature that was first released with the iPhone 5S and later used on later iPhone models and iPads. It is one of the three security options included with Apple devices, the others being the Passcode and Face ID.

Usage[]

Touch ID is activated through a fingerprint sensor built into a Home button with a sapphire surface, and can be used for unlocking an iPhone or iPad, as well as authorizing purchases. The sensor can also be found at the top-right corner of keyboard of the MacBook or the Magic Keyboard for Apple M1-based Macs.

To setup the Touch ID, you have to place your finger on the sensor, and lift it for the sensor to read your fingerprint. After the completion, you can use the Touch ID to unlock, sign in, and purchase from the App Store or iTunes.

Software Lock[]

The Touch ID sensor (home button) has an iOS software lock that prevents the home button from being replaced from one iPhone to another one. If swapped, the Touch ID fingerprint reading function will be disabled, and an error message shows up on the iPhone upon turning on at the home screen. The home button with Touch ID are paired to each individual iPhone.

From the iPhone 5s, to iPhone 6s, the Touch ID gets disabled after a replacement, but all the other features such as exiting apps, and activating Siri still functions. However the iPhone 7, iPhone 8, iPhone SE 2nd and 3rd generation uses a solid state home button, and a replacement completely disables the entire home button. Meaning that the software lock in iOS renders the whole home button useless. Only Apple can reactivate the home button. This is an anti-repair practice done by Apple to prevent 3rd party and self repairs done on the device. The only workaround to this issue is to use the Assistive Touch feature, or pay Apple to replace or reactive the home button.