Boot storage is the storage layer a system reads first when starting up, before the operating system is fully running. It may hold boot code, firmware-related data, recovery images, or the files needed to load the operating environment. Because it sits at the start of the trust chain, it is often treated as highly sensitive infrastructure rather than ordinary disk space.
In cyber security, boot storage matters because flaws there can let an attacker alter startup components, hide persistence, or interfere with validation before defenses are active. Weaknesses in this layer may lead to unauthorized code changes, boot-time tampering, or bypasses of integrity checks. Defenders protect it with secure boot, signed updates, access controls, and careful inventory of devices that use vendor-specific boot storage modules.