diff --git a/core/product.mk b/core/product.mk
index 8976dd9..19e760b 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -360,6 +360,11 @@
 _product_list_vars += PRODUCT_PACKAGE_NAME_OVERRIDES
 _product_list_vars += PRODUCT_CERTIFICATE_OVERRIDES
 
+# A list of <overridden-apex>:<override-apex> pairs that specifies APEX module
+# overrides to be applied to the APEX names in the boot jar variables
+# (PRODUCT_BOOT_JARS, PRODUCT_UPDATABLE_BOOT_JARS etc).
+_product_list_vars += PRODUCT_BOOT_JAR_MODULE_OVERRIDES
+
 # Controls for whether different partitions are built for the current product.
 _product_single_value_vars += PRODUCT_BUILD_SYSTEM_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_SYSTEM_OTHER_IMAGE
diff --git a/core/product_config.mk b/core/product_config.mk
index 11ffade..d703ee3 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -238,6 +238,19 @@
 PRODUCT_BOOT_JARS := $(foreach pair,$(PRODUCT_BOOT_JARS), \
   $(if $(findstring :,$(pair)),,platform:)$(pair))
 
+# Replaces references to overridden boot jar modules in a boot jars variable.
+# $(1): Name of a boot jars variable with <apex>:<jar> pairs.
+define replace-boot-jar-module-overrides
+  $(foreach pair,$(PRODUCT_BOOT_JAR_MODULE_OVERRIDES),\
+    $(eval _rbjmo_from := $(call word-colon,1,$(pair)))\
+    $(eval _rbjmo_to := $(call word-colon,2,$(pair)))\
+    $(eval $(1) := $(patsubst $(_rbjmo_from):%,$(_rbjmo_to):%,$($(1)))))
+endef
+
+$(call replace-boot-jar-module-overrides,PRODUCT_BOOT_JARS)
+$(call replace-boot-jar-module-overrides,PRODUCT_UPDATABLE_BOOT_JARS)
+$(call replace-boot-jar-module-overrides,ART_APEX_JARS)
+
 # The extra system server jars must be appended at the end after common system server jars.
 PRODUCT_SYSTEM_SERVER_JARS += $(PRODUCT_SYSTEM_SERVER_JARS_EXTRA)
 
diff --git a/core/rbe.mk b/core/rbe.mk
index 91606d4..19c0e42 100644
--- a/core/rbe.mk
+++ b/core/rbe.mk
@@ -34,6 +34,12 @@
     cxx_compare := false
   endif
 
+  ifdef RBE_CXX_COMPARE
+    cxx_compare := $(RBE_CXX_COMPARE)
+  else
+    cxx_compare := "false"
+  endif
+
   ifdef RBE_JAVAC_EXEC_STRATEGY
     javac_exec_strategy := $(RBE_JAVAC_EXEC_STRATEGY)
   else
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 0c91a14..c9e3e80 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -240,7 +240,7 @@
     #  It must be of the form "YYYY-MM-DD" on production devices.
     #  It must match one of the Android Security Patch Level strings of the Public Security Bulletins.
     #  If there is no $PLATFORM_SECURITY_PATCH set, keep it empty.
-      PLATFORM_SECURITY_PATCH := 2021-02-05
+      PLATFORM_SECURITY_PATCH := 2021-03-05
 endif
 .KATI_READONLY := PLATFORM_SECURITY_PATCH
 
diff --git a/target/product/generic_system.mk b/target/product/generic_system.mk
index 9580ade..1f310c9 100644
--- a/target/product/generic_system.mk
+++ b/target/product/generic_system.mk
@@ -32,8 +32,6 @@
 PRODUCT_PACKAGES += \
     LiveWallpapersPicker \
     PartnerBookmarksProvider \
-    PresencePolling \
-    RcsService \
     Stk \
     Tag \
     TimeZoneUpdater \