Which feature permanently alters the state of a transistor on a chip if the bootloader is modified?

• A. Bootloader Security
• B. Device Hardening
• C. End of Life (EOL)
• D. eFuse

Answer: (D)

The key idea is a hardware one-time programmable feature that permanently changes a transistor’s state: an eFuse. An eFuse is a fuse-like element on a chip that, once blown or programmed, cannot be reversed. This makes it ideal for enforcing security decisions that must survive power cycles and even factory resets. In the context of boot security, burning an eFuse can lock in a tamper-detection or secure-boot condition so that if the bootloader is modified, the device can recognize the change and refuse to boot or enter a locked state. Because the state change is permanent, it provides a durable safeguard against reprogramming attacks.

Other terms describe strategies or lifecycle concepts rather than a hardware mechanism that permanently alters the chip. Bootloader security refers to protecting the boot process through software and cryptographic checks. Device hardening is the broader set of measures to reduce attack surfaces. End of Life denotes a product’s lifecycle phase, not a hardware state change.