Activation Lock now extends to the serials of the parts inside every iPhone since Apple knows the S/N of everything. If you pull the battery off an Activation Locked phone and put it in another phone it's going to freak out and complain the part is pairing-locked and won't pair to your device but it'll be baseline usable. You'll just keep getting nasty nags in the Settings letting you know you're using stolen parts.

https://support.apple.com/guide/security/activation-lock-sec...

As of iOS 27 beta, there's now an additional "partner finance lock" status that will also be an available parts-lock status (to prevent a 'leased' device from being parted out).

https://9to5mac.com/2026/07/21/ios-27-code-suggests-apple-co...