EEPROM (Electrically Erasable Programmable Read-Only Memory) is non-volatile memory that keeps its contents after power is removed. Devices use it to store firmware, bootloaders, calibration data, and board settings that must survive reboots and battery loss. Because it is readable and rewritable, manufacturers can update it during maintenance or upgrades without replacing the chip.
In cyber security, EEPROM matters because code stored there runs very early in startup, often before the operating system and many defenses are active. If an attacker can tamper with it, they may alter boot behavior, weaken hardware checks, or create persistence that survives disk wipes and OS reinstalls. Defenders protect EEPROM by using signed firmware updates, restricting write access, validating known-good versions, and keeping recovery methods available for failed or suspicious updates. On embedded systems and single-board computers, EEPROM often becomes a control point for compatibility and trust.