UM2262 Rev 6
39/94
UM2262
Package description
93
6.2.7
Secure Boot and Secure Firmware Upgrade (SBSFU) application
Secure Boot (Root of Trust)
•
Checks and applies the security mechanisms of STM32 platform to protect critical
operations and secrets from attacks
•
Authenticates and verifies the user application before each execution
Local download via UART Virtual COM
•
Detects firmware download requests
•
Downloads in STM32 Flash memory the new encrypted firmware image (
encrypted firmware) via the UART Virtual COM using Ymodem protocol and the Tera
Term tool (see
FW installation management
•
Detects new FW version to install
–
From local download service via the UART interface
–
Downloaded via user application (dual-image variant only)
•
Secures FW upgrade:
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Authentication and integrity check
–
FW decryption
–
FW installation
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Anti-rollback mechanisms to avoid re-installation of previous firmware version
•
Supports single image for maximizing the user application size
•
Supports dual image for safe image programming
–
Resume firmware installation: in case of power off during the installation process,
installation is resumed at next power on.
–
Multiple firmware images management: handles two firmware images (UserApp1
image and UserApp2 image) stored in internal STM32 Flash. A SWAP area is
used in order to limit memory overhead needed during firmware installation (refer
to
to get details about multiple images management).
–
Partial update: flexibility to update the complete firmware image or a portion of it.
Note
For the STM32WB Series, an example of standalone loader is provided. Refer to
for details.