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One of the more common tasks is to update the system firmware version so the next time a system firmware update capsule is built with new features or bug fixes, it has a new version value, version string, and potentially prevents rolling back to earlier firmware versions. This version information is implemented in the .aslc file associated with the System Firmware Descriptor PEIM. The implementation of this PEIM is covered here.

Change Version Value and Version String

The following is a portion of the SystemFirmwareDescriptor.aslc that contains the version values and strings.

#define CURRENT_FIRMWARE_VERSION            0x00000010
#define CURRENT_FIRMWARE_VERSION_STRING     L"Version 0.0.0.16"
#define LOWEST_SUPPORTED_FIRMWARE_VERSION   0x0000000A

• CURRENT_FIRMWARE_VERSION - The hex value (e.g. 0x00000002) of the firmware in the system firmware update capsule.
• CURRENT_FIRMWARE_VERSION_STRING - A Unicode string that is the name of the firmware version in system firmware update capsule. This Unicode string is only used to display more detailed version information.
• LOWEST_SUPPORTED_FIRMWARE_VERSION - A hex value(e.g. 0x00000002) that is the lowest CURRENT_FIRMWARE_VERSION value that this firmware version allows to be rolled back to. For example, if the firmware on a platform has a CURRENT_FIRMWARE_VERSION of 0x00000010 and a LOWEST_SUPPORTED_FIRMWARE_VERSION of 0x0000000A, then the current firmware would allow system firmware update capsule's with CURRENT_FIRMWARE_VERSION values of 0x000000A or higher to be installed.

Verify Version Value and Version String

Build a firmware image with the updated version information and update a target platform with the new version of firmware. Run CapsuleApp.efi -P to view the Firmware Management Protocol details. In the example below,

• CURRENT_FIRMWARE_VERSION is in the field called Version with a value of 0x10.
• CURRENT_FIRMWARE_VERSION_STRING is in the field called VersionName with a value of "Version 0.0.0.16".
• LOWEST_SUPPORTED_FIRMWARE_VERSION is in the field called LowestSupportedImageVersion with a value of 0xA.

############
# FMP DATA #
############
FMP (0) ImageInfo:
  DescriptorVersion  - 0x3
  DescriptorCount    - 0x1
  DescriptorSize     - 0x60
  PackageVersion     - 0xFFFFFFFF
  PackageVersionName - "Verify Test Signing Key"
  ImageDescriptor (0)
    ImageIndex                  - 0x1
    ImageTypeId                 - 553B20F9-9154-46CE-8142-80E2AD96CD92
    ImageId                     - 0x4B545F4B52415551
    ImageIdName                 - "QuarkPlatformFdVerifyTestSigningKey"
    Version                     - 0x10
    VersionName                 - "Version 0.0.0.16"
    Size                        - 0x800000
    AttributesSupported         - 0xF
      IMAGE_UPDATABLE           - 0x1
      RESET_REQUIRED            - 0x2
      AUTHENTICATION_REQUIRED   - 0x4
      IN_USE                    - 0x8
      UEFI_IMAGE                - 0x0
    AttributesSetting           - 0xF
      IMAGE_UPDATABLE           - 0x1
      RESET_REQUIRED            - 0x2
      AUTHENTICATION_REQUIRED   - 0x4
      IN_USE                    - 0x8
      UEFI_IMAGE                - 0x0
    Compatibilities             - 0x0
      COMPATIB_CHECK_SUPPORTED  - 0x0
    LowestSupportedImageVersion - 0xA
    LastAttemptVersion          - 0x0
    LastAttemptStatus           - 0x0 (Success)
    HardwareInstance            - 0x0
FMP (0) PackageInfo - Unsupported

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