Firmware Interface Table

BIOS Specification

ID 599500
Date 04/14/2023
Intel Confidential

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BIOS Startup Module (Type 7) Rules

Record Types 7 is used by legacy Intel® TXT FIT boot only and is not needed, if latter is not used.

  1. There can be zero or more BIOS Startup Module Entries in the FIT. For FIT boot, support with BPT do not have to include Type 7 entry. Otherwise, at least one BIOS Startup Module Entry in the FIT is required for FIT boot support.
  2. For purpose of this specification, BIOS Startup code is defined as the code that gets control at reset vector and continues the chain of trust in TCG compliant fashion. In addition, this code may also configure memory and SMRAM.
  3. In order to enable more flexible flash layout, BIOS Init code can be split in multiple BIOS Startup Modules. Each BIOS Startup Module will have one corresponding Type 7 entry. Each Type 7 entry describes address and size of the corresponding BIOS Startup Module.
  4. Each Type 7 entry must point to an address that is accessible by the processor at reset vector. The address should be within the low 4 GB of address space.
  5. At least one BIOS Startup Module must encompass Reset vector.
  6. At least one BIOS Startup Module must encompass FIT pointer.
  7. BIOS Startup Module should not encompass Type 0x9 record, if signature verification mechanism is used.
  8. Various BIOS Startup Modules cannot overlap with each other.
  9. None of the BIOS Startup Module can overlap with Startup ACM (refer to Section 4.4).
  10. The C_​V bit in this entry should be clear to 0.
  11. The Size field indicates the size of the BIOS startup module in 16-byte multiples. Example: Value of 0x1000 indicates a 64 KB BIOS Startup Module.
  12. The Version field should be set to 0x0100.