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authorMasahisa Kojima <masahisa.kojima@linaro.org>2023-06-22 17:06:29 +0900
committerHeinrich Schuchardt <heinrich.schuchardt@canonical.com>2023-07-15 11:20:41 +0200
commit345a8b15acf228c4a429f6569c34cbc0232e76eb (patch)
tree385c25c3bd11311d53cc32f218a59e0303bed8c4
parenta12b36434d822ef1c4f6631314a8ea229e68c520 (diff)
doc: uefi: enhance anti-rollback documentation
To enforce anti-rollback to any older version, dtb must be always update manually. This should be described in the documentation. This commit also adds the recommendation that secure system should not enable the fdt command because lowest-supported-version property in device tree can be changed by fdt command. Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
-rw-r--r--doc/develop/uefi/uefi.rst7
1 files changed, 7 insertions, 0 deletions
diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst
index 6626ceec52b..a7a41f2facf 100644
--- a/doc/develop/uefi/uefi.rst
+++ b/doc/develop/uefi/uefi.rst
@@ -552,6 +552,13 @@ update using a capsule file with --fw-version of 5, the update will fail.
When the --fw-version in the capsule file is updated, lowest-supported-version
in the dtb might be updated accordingly.
+If user needs to enforce anti-rollback to any older version,
+the lowest-supported-version property in dtb must be always updated manually.
+
+Note that the lowest-supported-version property specified in U-Boot's control
+device tree can be changed by U-Boot fdt command.
+Secure systems should not enable this command.
+
To insert the lowest supported version into a dtb
.. code-block:: console