How to be sure of Apple genuine parts - "Unknown part" warning possible to circumvent

Re: “… How do I know for sure that a 'refurbished' iPhone has genuine Apple parts …”

By purchasing from:

Certified Refurbished Products - Apple

Only buy refurbished devices straight from Apple.

As long as there is a strong economic incentive for unscrupulous organizations to defraud those chasing deep discounts …

… such fraud will continue.

Apple devices - being relatively pricey - tend to drive this activity.

The ONLY way to be “sure” is to have full trust and confidence in both the entity from whom you are purchasing AND the provenance of the device.

In the modern “used phone” marketplace, this confidence is difficult to achieve.

Caveat Emptor.