If you picked up a new iPhone 5s this year, you’d better take good care of its home button, because you can no longer pick up a cheap replacement on eBay and fit it yourself. The repair experts at mendmyi have discovered that Apple pairs every Touch ID sensor with an A7 chip, and if you install a home button that doesn’t match up, Touch ID simply won’t work.
The discovery was made when a mendmyi customer sent in their iPhone 5s for the color lab treatment, which is when its aluminum parts — including the handset’s main chassis — are replaced with colorful ones. When they received their handset back, they found Touch ID wasn’t working.
It took a little while and lots of digging to figure out what the issue was, but mendmyi eventually found that a replacement home button was to blame.
“In order to try and rectify the problem, many steps were attempted. These included swapping out the Touch ID sensor for one verified to work, replacing the dock connector the Touch ID makes contact with, and even replacing the logic board itself,” iMore reports. “Nothing worked. It was baffling.”
Once the original home button was installed back into the device, Touch ID began working again. After further digging, mendmyi found that it’s actually the button’s flax cable — which connects it to the logic board — that is tied to an individual A7 chip.
But why? Does Apple do this just to be difficult, and to prevent us from buying cheap replacements when our home buttons die? Well, probably not. It’s more likely that these steps are taken to make Touch ID as secure as it possibly can be, and to eliminate the possibility that it could be hacked.
Apple has already explained to us that our fingerprints are not accessible by iOS apps, and that they are never stored on its servers or backed up to iCloud, so there’s no easy way for someone to get hold of them. And by tying Touch ID sensors to their accompanying A7 chips, Apple also rules out the possibility that hacked home buttons could intercept communications between the two.
Apple really has gone to great lengths to make Touch ID secure, then. For users, this is (mostly) great news, because it means it’s near impossible for anyone to get hold of the fingerprints stored on your iPhone. It may mean home buttons are very difficult to replace, but if you’re concerned about your privacy, this should give you peace of mind.