If the guided section was encoded with GenCrc32 tool the resulting 'EFI_GUID_DEFINED_SECTION.DataOffset' field points to the start of the meaningfull data that follows the CRC32 value. But if we want to decode the section with GenCrc32 tool we need to provide a buffer that includes the CRC32 value itself. Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com> Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn> Reviewed-by: Bob Feng <bob.c.feng@intel.com>