diff --git a/CleanSpec.mk b/CleanSpec.mk
index 7778118..64d84e3 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -369,6 +369,8 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
 
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/core/Makefile b/core/Makefile
index 7da3b23..22dcee1 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -204,6 +204,8 @@
 			BUILD_DISPLAY_ID="$(BUILD_DISPLAY_ID)" \
 			BUILD_NUMBER="$(BUILD_NUMBER)" \
 			PLATFORM_VERSION="$(PLATFORM_VERSION)" \
+			PLATFORM_SECURITY_PATCH="$(PLATFORM_SECURITY_PATCH)" \
+			PLATFORM_BASE_OS="$(PLATFORM_BASE_OS)" \
 			PLATFORM_SDK_VERSION="$(PLATFORM_SDK_VERSION)" \
 			PLATFORM_PREVIEW_SDK_VERSION="$(PLATFORM_PREVIEW_SDK_VERSION)" \
 			PLATFORM_VERSION_CODENAME="$(PLATFORM_VERSION_CODENAME)" \
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index efb2bee..483c8f2 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -24,6 +24,7 @@
 #     DEFAULT_APP_TARGET_SDK
 #     BUILD_ID
 #     BUILD_NUMBER
+#     SECURITY_PATCH
 #
 
 # Look for an optional file containing overrides of the defaults,
@@ -97,6 +98,22 @@
   endif
 endif
 
+ifeq "" "$(PLATFORM_SECURITY_PATCH)"
+  # Used to indicate the security patch that has been applied to the device.
+  # Can be an arbitrary string, but must be a single word.
+  #
+  # If there is no $PLATFORM_SECURITY_PATCH set, keep it empty.
+  PLATFORM_SECURITY_PATCH :=
+endif
+
+ifeq "" "$(PLATFORM_BASE_OS)"
+  # Used to indicate the base os applied to the device.
+  # Can be an arbitrary string, but must be a single word.
+  #
+  # If there is no $PLATFORM_BASE_OS set, keep it empty.
+  PLATFORM_BASE_OS :=
+endif
+
 ifeq "" "$(BUILD_ID)"
   # Used to signify special builds.  E.g., branches and/or releases,
   # like "M5-RC7".  Can be an arbitrary string, but must be a single
diff --git a/tools/buildinfo.sh b/tools/buildinfo.sh
index 6cd9499..5c199b8 100755
--- a/tools/buildinfo.sh
+++ b/tools/buildinfo.sh
@@ -11,6 +11,8 @@
 echo "ro.build.version.codename=$PLATFORM_VERSION_CODENAME"
 echo "ro.build.version.all_codenames=$PLATFORM_VERSION_ALL_CODENAMES"
 echo "ro.build.version.release=$PLATFORM_VERSION"
+echo "ro.build.version.security_patch=$PLATFORM_SECURITY_PATCH"
+echo "ro.build.version.base_os=$PLATFORM_BASE_OS"
 echo "ro.build.date=`date`"
 echo "ro.build.date.utc=`date +%s`"
 echo "ro.build.type=$TARGET_BUILD_TYPE"