Index: head/sys/dev/sfxge/common/siena_flash.h
===================================================================
--- head/sys/dev/sfxge/common/siena_flash.h
+++ head/sys/dev/sfxge/common/siena_flash.h
@@ -131,7 +131,14 @@
 						/* the key, or 0xffff if unsigned. (Otherwise set to 0) */
 	efx_byte_t	mumfw_subtype;		/* MUM & SUC images: subtype. (Otherwise set to 0) */
 	efx_byte_t	reserved_b[3];		/* (set to 0) */
-	efx_dword_t	reserved_c[6];		/* (set to 0) */
+	efx_dword_t	security_level;		/* This number increases every time a serious security flaw */
+						/* is fixed. A secure NIC may not downgrade to any image */
+						/* with a lower security level than the current image. */
+						/* Note: The number in this header should only be used for */
+						/* determining the level of new images, not to determine */
+						/* the level of the current image as this header is not */
+						/* protected by a CMAC. */
+	efx_dword_t	reserved_c[5];		/* (set to 0) */
 } siena_mc_boot_hdr_t;
 
 #define	SIENA_MC_BOOT_HDR_PADDING \