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| -rw-r--r-- | doc/develop/uefi/uefi.rst | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst index ffe25ca231..30b90a09d5 100644 --- a/doc/develop/uefi/uefi.rst +++ b/doc/develop/uefi/uefi.rst @@ -318,6 +318,33 @@ Run the following command --guid <image GUID> \ <capsule_file_name> +The UEFI specification does not define the firmware versioning mechanism. +EDK II reference implementation inserts the FMP Payload Header right before +the payload. It coutains the fw_version and lowest supported version, +EDK II reference implementation uses these information to implement the +firmware versioning and anti-rollback protection, the firmware version and +lowest supported version is stored into EFI non-volatile variable. + +In U-Boot, the firmware versioning is implemented utilizing +the FMP Payload Header same as EDK II reference implementation, +reads the FMP Payload Header and stores the firmware version into +"FmpStateXXXX" EFI non-volatile variable. XXXX indicates the image index, +since FMP protocol handles multiple image indexes. + +To add the fw_version into the FMP Payload Header, +add --fw-version option in mkeficapsule tool. + +.. code-block:: console + + $ mkeficapsule \ + --index <index> --instance 0 \ + --guid <image GUID> \ + --fw-version 5 \ + <capsule_file_name> + +If the --fw-version option is not set, FMP Payload Header is not inserted +and fw_version is set as 0. + Performing the update ********************* |