Final assembly is the stage where separate parts are put together into a finished device. In electronics, this can include mounting components, closing the enclosure, loading firmware, and preparing the product for shipping. It is usually less specialized than chip fabrication, so it is often moved to different countries or contractors more easily.
In cyber security, final assembly matters because it is a late point in the hardware supply chain where provenance can be lost and malicious changes can be introduced. Attackers may exploit weak controls to swap parts, install altered firmware, or insert counterfeit components. Defenders use vendor audits, serial tracking, secure boot, tamper-evident packaging, and inspection to reduce this risk. Even when the sensitive parts are made elsewhere, a compromised final assembly line can still affect the trustworthiness of the finished product.