Bootloader Support in Simplicity SDK for Zephyr#

MCUboot#

MCUboot is the default bootloader used in the Simplicity SDK for Zephyr. It provides a secure, flexible, and hardware-agnostic foundation for authenticated boot and firmware upgrade workflows on Silicon Labs Series 2 devices.

The SDK integrates MCUboot with Silicon Labs hardware features, including Secure Engine (SE) support, hardware-accelerated PSA Crypto operations, and Sysbuild-based application + bootloader builds.

Secure Boot Overview#

Silicon Labs Series 2 devices support two Secure Engine variants:

• Hardware Secure Engine (HSE) — supports PSA Crypto builtin keys stored in SE OTP and hardware-accelerated ECDSA verification.

• Virtual Secure Engine (VSE) — uses an embedded public key within the MCUboot image and performs hardware-accelerated ECDSA verification using PSA Crypto transparent drivers.

Both variants enforce authenticated boot using digital signatures.

For full details, see:

• MCUboot Secure Boot for Series 2 Devices

MCUboot Features in the SDK#

The Simplicity SDK for Zephyr enables:

• Secure boot with signature verification (HSE and VSE)

• Firmware image management and upgrade support

• Integration with Sysbuild for coordinated bootloader + application builds

• Hardware-accelerated signature verification on HSE and VSE devices

• Embedded-key verification on VSE-based devices