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Apple today announced that it will soon start selling customers the genuine parts and tools needed to repair their own iPhone. These parts will initially be available for iPhone 12 and iPhone 13 devices, with the initial phase of the program focusing on the most commonly serviced modules: display, battery, and camera. Other parts will become available at a later date.
Notably, repairing an iPhone yourself won't void your warranty. Adding additional damage may, however.
Customers who return their old busted parts to Apple for recycling will be given store credit.
You don't need their permission.