SLUUDG7A December   2025  – November 2026 MSPM33C321A , MSPM33C321A-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Overview of Security Functionality
    1. 1.1 Terminology
    2. 1.2 Platform Security Enablers
  5. 2Device Security Model
    1. 2.1 Device Identity
    2. 2.2 Initial Conditions at Boot
    3. 2.3 Boot Configuration Routine (BCR)
    4. 2.4 Bootstrap Loader (BSL)
    5. 2.5 Lifecycle Management
      1. 2.5.1 Lifecycle Transitions
    6. 2.6 Boot Service
    7. 2.7 Boot Flow
    8. 2.8 User-Specified Security Policies
      1. 2.8.1 Boot Configuration Routine (BCR) Policies
        1. 2.8.1.1 Serial Wire Debug Related Policies
          1. 2.8.1.1.1 No Restrictions Scenario
          2. 2.8.1.1.2 Custom Restrictions Scenario
          3. 2.8.1.1.3 Fully Restricted Scenario
        2. 2.8.1.2 Bootstrap Loader (BSL) Enable/Disable Policy
        3. 2.8.1.3 Flash Memory Protection and Integrity Related Policies
          1. 2.8.1.3.1 Locking the Application (MAIN) Flash Memory
          2. 2.8.1.3.2 Locking the Configuration (NONMAIN) Flash Memory
          3. 2.8.1.3.3 Security and Privilege Protection on Application (MAIN, DATA) Flash Memory
          4. 2.8.1.3.4 Verifying Integrity of Application (MAIN) Flash Memory
      2. 2.8.2 Bootstrap Loader (BSL) Security Policies
        1. 2.8.2.1 BSL Access Password
        2. 2.8.2.2 BSL Read-out Policy
        3. 2.8.2.3 BSL Security Alert Policy
      3. 2.8.3 Customer Secure Code (CSC) Security Policies
        1. 2.8.3.1 CSC Enforced Bankswap
        2. 2.8.3.2 CSC Key Write to KEYSTORE
      4. 2.8.4 Configuration Data Error Resistance
        1. 2.8.4.1 CRC-Backed Configuration Data
          1. 2.8.4.1.1 BCR Configuration CRC Fail Handling
          2. 2.8.4.1.2 TI Factory Trim Data CRC Fail Handling
        2. 2.8.4.2 BSL Configuration CRC Fail Handling
        3. 2.8.4.3 16-bit Pattern Match for Critical Fields
  6. 3Secure Boot
    1. 3.1 MCUBoot
    2. 3.2 ROM-based Secure Boot
      1. 3.2.1 ROM-based Secure Boot Flow
      2. 3.2.2 Customer Key Storage
        1. 3.2.2.1 Key Revocation Using the DSSM
        2. 3.2.2.2 Key Revocation Using the Firmware Update
      3. 3.2.3 Anti‑rollback Protection
    3. 3.3 CSC-based Secure Boot
      1. 3.3.1 CSC-based Secure Boot Flow
      2. 3.3.2 FLASH Memory Map
      3. 3.3.3 CSC Key Storage
        1. 3.3.3.1 Key Storage for CSC-based Secure Boot
        2. 3.3.3.2 KEYSTORE for AES
      4. 3.3.4 Bank Swap
      5. 3.3.5 CSC Protection
    4. 3.4 Two Stage Secure Boot
      1. 3.4.1 Two Stage Secure Boot Flow
  7. 4Secure Execution Environment
    1. 4.1 TrustZone
      1. 4.1.1 Implementation Defined Attribution Unit
      2. 4.1.2 Security Attribution Unit
        1. 4.1.2.1 Defining a Region as Secure
      3. 4.1.3 TrustZone Software Development
        1. 4.1.3.1 Defining Functions as Secure and Non-secure
    2. 4.2 Memory Protection Unit
      1. 4.2.1 TrustZone and MPU
    3. 4.3 Global Security Controller
      1. 4.3.1 GSC Memory Configuration
        1. 4.3.1.1 Security Exceptions Through the GSC and SAU
        2. 4.3.1.2 Privilege Exceptions With GSC and MPU
  8. 5Secure Storage
    1. 5.1 Write Erase Protection
      1. 5.1.1 Global Security Controller Configuration on WEP
      2. 5.1.2 NONMAIN FLASH Configuration on WEP
    2. 5.2 FLASH Hide Protection
      1. 5.2.1 Global Security Controller Configuration on HDP
    3. 5.3 Secure Key Storage
    4. 5.4 Data Integrity Verification
    5. 5.5 Secure and Privilege Protection
    6. 5.6 Hardware Monotonic Counter
  9. 6Security Modules
    1. 6.1 AESADV
      1. 6.1.1 AES Overview
      2. 6.1.2 AES Usage
        1. 6.1.2.1 Configuration
        2. 6.1.2.2 Setup
        3. 6.1.2.3 Operation
    2. 6.2 Keystore
      1. 6.2.1 Overview
      2. 6.2.2 Keystore Usage
        1. 6.2.2.1 Configuration
        2. 6.2.2.2 Setup
        3. 6.2.2.3 Operation
    3. 6.3 SHA2
      1. 6.3.1 SHA Introduction
        1. 6.3.1.1 SHA Features
      2. 6.3.2 SHA Performance
      3. 6.3.3 SHA Usage
        1. 6.3.3.1 Configuration
        2. 6.3.3.2 Setup
        3. 6.3.3.3 Operation
    4. 6.4 PKA
      1. 6.4.1 PKA Introduction
        1. 6.4.1.1 PKA features
      2. 6.4.2 PKA Usage
        1. 6.4.2.1 Configuration
        2. 6.4.2.2 Setup
        3. 6.4.2.3 Operation
    5. 6.5 PQC
      1. 6.5.1 ML-DSA
        1. 6.5.1.1 ML-DSA Introduction
        2. 6.5.1.2 ML-DSA Usage
          1. 6.5.1.2.1 Configuration
          2. 6.5.1.2.2 Setup
          3. 6.5.1.2.3 Operation
  10. 7Revision History

3.1 MCUBoot

MCUBoot is an open-source secure bootloader to manage the startup process of a device and verify that only authentic, authorized, and intact firmware is executed. Both secure boot methods follow MCUBoot image format, as shown in Figure 3-1.

  • Image Header - a fixed-size structure (32 bytes) that contains essential metadata about the firmware image, including the header magic (0x96F3B83D), image size and image version. The image header is located at the address 0x200 bytes (by default) before the application interrupt vectors.
  • Image payload - Original Unsigned Application Code
    • Interrupt Vectors
    • Application code
  • Image Type-Length-Value (TLV) - contains metadata, cryptographic hashes, signatures, and other information. MCUBOOT defines Type-length-value records (TLV) which are placed after the end of the image. The TLVs defined in MSPM33 CSC includes: TLV magic (0x6907), image hash, ECDSA public key hash, ECDSA signature, MLDSA public key hash and MLDSA signature. For more details, see mcuboot/docs/design.md at main · mcu-tools/mcuboot · GitHub.
  • Image Trailer - contains information used during the update process, especially during swap-based updates.

Image Header, Image TLV and Image Trailer: generated by signing tool imgtool, which is provided by MCUBOOT (located with python scripts in <mspm33_sdk_path>\source\third_party\mcuboot\scripts). These parts are generated and merged to a compiled application image in the CCS post-build step. There is a customer_secure_sample_image example in MSPM33 SDK which shows how a signed image is built in CCS.

The MCUBoot image format is a structured binary format that wraps the actual application code with specific metadata. This metadata is essential because it allows the secure boot to identify, verify, and manage the update process without needing to "guess" where the application starts or how to validate it.

MSPM33C MSPM33C321A MCUBoot Image Format Figure 3-1 MCUBoot Image Format

Figure 3-2 shows the general process to generate hashes, signatures and other metadata in TLV section. Figure 3-2 is related to example of CSC-based secure boot in SDK, which support both ECDSA_P256 and MLDSA-87.

To build up the image in MCUBoot format, users can use imgtool provided by MCUBoot. TI has included imgtool in the SDK.

MSPM33C MSPM33C321A Process to Generate Metadata in TLV Section Figure 3-2 Process to Generate Metadata in TLV Section

The following is the general image validation process:

  1. Check Image Magic
  2. If valid, compute image hash (on image header + image data)
  3. Find hash TLV and compare with computed hash
  4. If match, check for key TLV and signature TLV
  5. If found, verify signature using public key
  6. If a security counter is present, checks that it's newer than the current value