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iPhone “Unknown Part” and Parts and Service History, explained

Customers now check Settings after a repair, and an “Unknown Part” message can turn a good repair into an argument at the counter. Here's what Apple actually says each label means, which parts it tracks, and what to tell customers before you quote an aftermarket screen or battery. Every claim below links to Apple's own support page (checked October 29, 2026). Apple changes these rules with iOS updates, so re-check the linked pages for the newest models.

Where customers see it

On iOS 15.2 and later: Settings → General → About. A Parts and Service History section only shows up if the iPhone has been repaired, and if a part was serviced more than once, only the most recent service is shown (Apple: iPhone Parts and Service History).

What each label means

Apple says that when an Unknown part is detected, the iPhone shows a notification the first time it's unlocked after the repair and again five days later (source).

Which parts it tracks, by model

• Battery: iPhone XR, XS, XS Max, SE (2nd and 3rd generation) and later (Apple: genuine batteries).
• Display: iPhone 11 and later, not the iPhone SE (2nd and 3rd generation) (Apple: genuine displays).
• Camera: iPhone 12 and later (Apple: genuine cameras).

What actually stops working

• Most parts keep working. Apple says the Unknown message itself doesn't stop the iPhone, display, battery or camera from working, though it might lower trade-in value.
• Face ID and Touch ID can't be used to unlock, pay or sign in until those parts are calibrated (Apple: Repair Assistant).
• Cameras on the newest phones: on iPhone 18 Pro models and iPhone Duo, the camera won't work until the repair is finished with Repair Assistant. Apple also says that on iPhone 18 Pro models with a nongenuine display, the camera might be disabled (source).
• Aftermarket displays: Apple lists possible issues with nongenuine displays, including touch problems, wrong color or brightness, ambient light sensor problems and extra battery drain. Since 2024, Apple lets customers turn on True Tone with third-party displays “to the best performance that can be provided” (Apple's 2024 repair whitepaper, via MacRumors).
• Third-party batteries: since 2024, Apple shows battery health metrics such as capacity and cycle count for third-party batteries, with a notice that Apple can't verify them (source).

Genuine parts and Repair Assistant

Repair Assistant (Settings → General → About → Parts & Service History → Restart & Finish Repair) calibrates genuine parts on the phone itself. It needs Wi-Fi, more than 20% battery and the latest iOS. With iPhone 15 and later on iOS 18, genuine parts taken from another iPhone of the same model can be calibrated and show as Used (Apple: Repair Assistant).

What to tell customers before an aftermarket repair

1. Say it up front. Before quoting a soft OLED, hard OLED or incell screen or a non-Apple battery on a tracked model, tell the customer the phone will likely show “Unknown Part” in Settings and a notification after the repair. It's Apple's label, not a sign your repair failed.
2. Mention trade-in. Apple says an Unknown part might affect trade-in value. Customers planning to trade in soon may prefer a genuine part.
3. Set feature expectations. True Tone and battery health may behave differently on third-party parts, as described above. See the screen quality tiers guide and the replacement battery checklist.
4. Write it on the ticket. Note the part grade and that the customer was told about the message. That heads off a dispute later.
5. Test before you seal. Use the pre-install screen test so a bad panel goes back to the supplier, not out the door.

Common questions

Where do customers see Parts and Service History on an iPhone?

On iOS 15.2 and later: Settings, General, About. The Parts and Service History section only appears if the iPhone has been repaired.

What does “Unknown Part” mean?

Apple shows Unknown when a replaced part isn't a genuine Apple part, isn't working as expected, hasn't been verified and linked to that iPhone after the repair, or has been modified or can't be verified.

Does an Unknown Part message stop the phone from working?

Apple says the Unknown message doesn't affect the ability to use the iPhone, display, battery or camera, though it might affect trade-in value. Exceptions Apple lists: Face ID and Touch ID need calibration to work, and on iPhone 18 Pro models and iPhone Duo the camera won't work until a camera repair is finished.

Can a third-party battery show Battery Health?

Apple said in 2024 that it would show battery health metrics for third-party batteries with a notice that Apple can't verify them. Apple also warned that some third-party batteries sold as new were actually used, with health data altered.

Does True Tone work with an aftermarket screen?

Apple said in 2024 that customers can turn on True Tone with third-party displays “to the best performance that can be provided” and turn it off if it doesn't look right. Results can vary because True Tone depends on per-device calibration.

Can a genuine part from another iPhone be reused?

With iPhone 15 and later on iOS 18 and later, a genuine display, battery or camera taken from another iPhone shows as Used, and Repair Assistant can calibrate it.