diff --git a/core/Makefile b/core/Makefile
index 194e372..0ca61bc 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -83,7 +83,7 @@
 $(pcf_ignored_file):
 	echo "$(PRIVATE_IGNORED)" | tr " " "\n" >$@
 
-$(call dist-for-goals,droidcore,$(pcf_ignored_file):logs/$(notdir $(pcf_ignored_file)))
+$(call dist-for-goals,droidcore-unbundled,$(pcf_ignored_file):logs/$(notdir $(pcf_ignored_file)))
 
 pcf_ignored_file :=
 product_copy_files_ignored :=
@@ -586,7 +586,7 @@
 	@rm -f $@
 	@$(foreach s,$(STATS.MODULE_TYPE),echo "modules_type_make,$(s),$(words $(STATS.MODULE_TYPE.$(s)))" >>$@;)
 	@$(foreach s,$(STATS.SOONG_MODULE_TYPE),echo "modules_type_soong,$(s),$(STATS.SOONG_MODULE_TYPE.$(s))" >>$@;)
-$(call dist-for-goals,droidcore,$(BUILD_SYSTEM_STATS))
+$(call dist-for-goals,droidcore-unbundled,$(BUILD_SYSTEM_STATS))
 
 # -----------------------------------------------------------------
 # build /product/etc/security/avb/system_other.avbpubkey if needed
@@ -611,7 +611,7 @@
 $(SOONG_TO_CONVERT): $(SOONG_CONV_DATA) $(SOONG_TO_CONVERT_SCRIPT)
 	@rm -f $@
 	$(hide) $(SOONG_TO_CONVERT_SCRIPT) $< >$@
-$(call dist-for-goals,droidcore,$(SOONG_TO_CONVERT))
+$(call dist-for-goals,droidcore-unbundled,$(SOONG_TO_CONVERT))
 
 MK2BP_CATALOG_SCRIPT := build/make/tools/mk2bp_catalog.py
 MK2BP_REMAINING_HTML := $(PRODUCT_OUT)/mk2bp_remaining.html
@@ -625,7 +625,7 @@
 		--out_dir="$(OUT_DIR)" \
 		--mode=html \
 		> $@
-$(call dist-for-goals,droidcore,$(MK2BP_REMAINING_HTML))
+$(call dist-for-goals,droidcore-unbundled,$(MK2BP_REMAINING_HTML))
 
 MK2BP_REMAINING_CSV := $(PRODUCT_OUT)/mk2bp_remaining.csv
 $(MK2BP_REMAINING_CSV): $(SOONG_CONV_DATA) $(MK2BP_CATALOG_SCRIPT)
@@ -635,7 +635,7 @@
 		--out_dir="$(OUT_DIR)" \
 		--mode=csv \
 		> $@
-$(call dist-for-goals,droidcore,$(MK2BP_REMAINING_CSV))
+$(call dist-for-goals,droidcore-unbundled,$(MK2BP_REMAINING_CSV))
 
 # -----------------------------------------------------------------
 # Modules use -Wno-error, or added default -Wall -Werror
@@ -647,11 +647,11 @@
 	echo "# Modules added default -Wall" >> $@
 	for m in $(sort $(SOONG_MODULES_ADDED_WALL) $(MODULES_ADDED_WALL)); do echo $$m >> $@; done
 
-$(call dist-for-goals,droidcore,$(WALL_WERROR))
+$(call dist-for-goals,droidcore-unbundled,$(WALL_WERROR))
 
 # -----------------------------------------------------------------
 # C/C++ flag information for modules
-$(call dist-for-goals,droidcore,$(SOONG_MODULES_CFLAG_ARTIFACTS))
+$(call dist-for-goals,droidcore-unbundled,$(SOONG_MODULES_CFLAG_ARTIFACTS))
 
 # -----------------------------------------------------------------
 # Modules missing profile files
@@ -815,8 +815,13 @@
 
 # We just build this directly to the install location.
 INSTALLED_RAMDISK_TARGET := $(BUILT_RAMDISK_TARGET)
+$(INSTALLED_RAMDISK_TARGET): PRIVATE_DIRS := debug_ramdisk dev metadata mnt proc second_stage_resources sys
 $(INSTALLED_RAMDISK_TARGET): $(MKBOOTFS) $(INTERNAL_RAMDISK_FILES) $(INSTALLED_FILES_FILE_RAMDISK) | $(COMPRESSION_COMMAND_DEPS)
 	$(call pretty,"Target ramdisk: $@")
+	$(hide) mkdir -p $(addprefix $(TARGET_RAMDISK_OUT)/,$(PRIVATE_DIRS))
+ifeq (true,$(BOARD_USES_GENERIC_KERNEL_IMAGE))
+	$(hide) mkdir -p $(addprefix $(TARGET_RAMDISK_OUT)/first_stage_ramdisk/,$(PRIVATE_DIRS))
+endif
 	$(hide) $(MKBOOTFS) -d $(TARGET_OUT) $(TARGET_RAMDISK_OUT) | $(COMPRESSION_COMMAND) > $@
 
 .PHONY: ramdisk-nodeps
@@ -4592,7 +4597,7 @@
 .PHONY: misc_info
 misc_info: $(INSTALLED_MISC_INFO_TARGET)
 
-droidcore: $(INSTALLED_MISC_INFO_TARGET)
+droidcore-unbundled: $(INSTALLED_MISC_INFO_TARGET)
 
 # -----------------------------------------------------------------
 # A zip of the directories that map to the target filesystem.
@@ -4846,7 +4851,7 @@
 
 ifdef BOARD_PREBUILT_BOOTLOADER
 $(BUILT_TARGET_FILES_PACKAGE): $(INSTALLED_BOOTLOADER_MODULE)
-droidcore: $(INSTALLED_BOOTLOADER_MODULE)
+droidcore-unbundled: $(INSTALLED_BOOTLOADER_MODULE)
 endif
 
 # Depending on the various images guarantees that the underlying
@@ -5434,7 +5439,7 @@
   $(PROFDATA_ZIP): $(SOONG_ZIP)
 	$(hide) $(SOONG_ZIP) -d -o $@ -C $(LLVM_PREBUILTS_BASE)/linux-x86/$(LLVM_PREBUILTS_VERSION) -f $(LLVM_PROFDATA) -f $(LIBCXX)
 
-  $(call dist-for-goals,droidcore,$(PROFDATA_ZIP))
+  $(call dist-for-goals,droidcore-unbundled,$(PROFDATA_ZIP))
 endif
 
 # -----------------------------------------------------------------
@@ -5613,7 +5618,7 @@
 	$(call build-superimage-target,$(INSTALLED_SUPERIMAGE_TARGET),\
           $(call intermediates-dir-for,PACKAGING,superimage_debug)/misc_info.txt)
 
-droidcore: $(INSTALLED_SUPERIMAGE_TARGET)
+droidcore-unbundled: $(INSTALLED_SUPERIMAGE_TARGET)
 
 # For devices that uses super image directly, the superimage target points to the file in $(PRODUCT_OUT).
 .PHONY: superimage
@@ -5699,7 +5704,7 @@
      $(MK_COMBINE_QEMU_IMAGE) -i $(INSTALLED_SYSTEM_QEMU_CONFIG) -o $@)
 
 systemimage: $(INSTALLED_QEMU_SYSTEMIMAGE)
-droidcore: $(INSTALLED_QEMU_SYSTEMIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_SYSTEMIMAGE)
 endif
 ifdef INSTALLED_VENDORIMAGE_TARGET
 INSTALLED_QEMU_VENDORIMAGE := $(PRODUCT_OUT)/vendor-qemu.img
@@ -5708,7 +5713,7 @@
 	(export SGDISK=$(SGDISK_HOST) SIMG2IMG=$(SIMG2IMG); $(MK_QEMU_IMAGE_SH) $(INSTALLED_VENDORIMAGE_TARGET))
 
 vendorimage: $(INSTALLED_QEMU_VENDORIMAGE)
-droidcore: $(INSTALLED_QEMU_VENDORIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_VENDORIMAGE)
 endif
 
 ifdef INSTALLED_RAMDISK_TARGET
@@ -5719,7 +5724,7 @@
 	@echo Create ramdisk-qemu.img
 	(cat $(INSTALLED_RAMDISK_TARGET) $(INTERNAL_VENDOR_RAMDISK_TARGET) > $(INSTALLED_QEMU_RAMDISKIMAGE))
 
-droidcore: $(INSTALLED_QEMU_RAMDISKIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_RAMDISKIMAGE)
 endif
 endif
 endif
@@ -5731,7 +5736,7 @@
 	(export SGDISK=$(SGDISK_HOST) SIMG2IMG=$(SIMG2IMG); $(MK_QEMU_IMAGE_SH) $(INSTALLED_PRODUCTIMAGE_TARGET))
 
 productimage: $(INSTALLED_QEMU_PRODUCTIMAGE)
-droidcore: $(INSTALLED_QEMU_PRODUCTIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_PRODUCTIMAGE)
 endif
 ifdef INSTALLED_SYSTEM_EXTIMAGE_TARGET
 INSTALLED_QEMU_SYSTEM_EXTIMAGE := $(PRODUCT_OUT)/system_ext-qemu.img
@@ -5740,7 +5745,7 @@
 	(export SGDISK=$(SGDISK_HOST) SIMG2IMG=$(SIMG2IMG); $(MK_QEMU_IMAGE_SH) $(INSTALLED_SYSTEM_EXTIMAGE_TARGET))
 
 systemextimage: $(INSTALLED_QEMU_SYSTEM_EXTIMAGE)
-droidcore: $(INSTALLED_QEMU_SYSTEM_EXTIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_SYSTEM_EXTIMAGE)
 endif
 ifdef INSTALLED_ODMIMAGE_TARGET
 INSTALLED_QEMU_ODMIMAGE := $(PRODUCT_OUT)/odm-qemu.img
@@ -5749,7 +5754,7 @@
 	(export SGDISK=$(SGDISK_HOST); $(MK_QEMU_IMAGE_SH) $(INSTALLED_ODMIMAGE_TARGET))
 
 odmimage: $(INSTALLED_QEMU_ODMIMAGE)
-droidcore: $(INSTALLED_QEMU_ODMIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_ODMIMAGE)
 endif
 
 ifdef INSTALLED_VENDOR_DLKMIMAGE_TARGET
@@ -5759,7 +5764,7 @@
 	(export SGDISK=$(SGDISK_HOST); $(MK_QEMU_IMAGE_SH) $(INSTALLED_VENDOR_DLKMIMAGE_TARGET))
 
 vendor_dlkmimage: $(INSTALLED_QEMU_VENDOR_DLKMIMAGE)
-droidcore: $(INSTALLED_QEMU_VENDOR_DLKMIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_VENDOR_DLKMIMAGE)
 endif
 
 ifdef INSTALLED_ODM_DLKMIMAGE_TARGET
@@ -5769,7 +5774,7 @@
 	(export SGDISK=$(SGDISK_HOST); $(MK_QEMU_IMAGE_SH) $(INSTALLED_ODM_DLKMIMAGE_TARGET))
 
 odm_dlkmimage: $(INSTALLED_QEMU_ODM_DLKMIMAGE)
-droidcore: $(INSTALLED_QEMU_ODM_DLKMIMAGE)
+droidcore-unbundled: $(INSTALLED_QEMU_ODM_DLKMIMAGE)
 endif
 
 QEMU_VERIFIED_BOOT_PARAMS := $(PRODUCT_OUT)/VerifiedBootParams.textproto
@@ -5780,7 +5785,7 @@
     $(INSTALLED_SYSTEMIMAGE_TARGET) $(QEMU_VERIFIED_BOOT_PARAMS))
 
 systemimage: $(QEMU_VERIFIED_BOOT_PARAMS)
-droidcore: $(QEMU_VERIFIED_BOOT_PARAMS)
+droidcore-unbundled: $(QEMU_VERIFIED_BOOT_PARAMS)
 
 endif
 # -----------------------------------------------------------------
diff --git a/core/android_soong_config_vars.mk b/core/android_soong_config_vars.mk
index 74558f5..a029985 100644
--- a/core/android_soong_config_vars.mk
+++ b/core/android_soong_config_vars.mk
@@ -28,6 +28,8 @@
 
 $(call add_soong_config_var,ANDROID,TARGET_ENABLE_MEDIADRM_64)
 $(call add_soong_config_var,ANDROID,BOARD_USES_ODMIMAGE)
+$(call add_soong_config_var,ANDROID,BOARD_USES_RECOVERY_AS_BOOT)
+$(call add_soong_config_var,ANDROID,BOARD_BUILD_SYSTEM_ROOT_IMAGE)
 
 # TODO(b/172480615): Remove when platform uses ART Module prebuilts by default.
 ifeq (,$(filter art_module,$(SOONG_CONFIG_NAMESPACES)))
diff --git a/core/config.mk b/core/config.mk
index d1746ef..e30ff3f 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -603,7 +603,7 @@
 # Path to tools.jar
 HOST_JDK_TOOLS_JAR := $(ANDROID_JAVA8_HOME)/lib/tools.jar
 
-APICHECK_COMMAND := $(JAVA) -Xmx4g -jar $(APICHECK) --no-banner --compatible-output=no
+APICHECK_COMMAND := $(JAVA) -Xmx4g -jar $(APICHECK) --no-banner
 
 # Boolean variable determining if the allow list for compatible properties is enabled
 PRODUCT_COMPATIBLE_PROPERTY := true
@@ -792,6 +792,7 @@
     28.0 \
     29.0 \
     30.0 \
+    31.0 \
 
 .KATI_READONLY := \
     PLATFORM_SEPOLICY_COMPAT_VERSIONS \
diff --git a/core/main.mk b/core/main.mk
index 401fb04..0393bee 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1574,9 +1574,10 @@
 .PHONY: vbmetavendorimage
 vbmetavendorimage: $(INSTALLED_VBMETA_VENDORIMAGE_TARGET)
 
-# Build files and then package it into the rom formats
-.PHONY: droidcore
-droidcore: $(filter $(HOST_OUT_ROOT)/%,$(modules_to_install)) \
+# The droidcore-unbundled target depends on the subset of targets necessary to
+# perform a full system build (either unbundled or not).
+.PHONY: droidcore-unbundled
+droidcore-unbundled: $(filter $(HOST_OUT_ROOT)/%,$(modules_to_install)) \
     $(INSTALLED_SYSTEMIMAGE_TARGET) \
     $(INSTALLED_RAMDISK_TARGET) \
     $(INSTALLED_BOOTIMAGE_TARGET) \
@@ -1634,6 +1635,11 @@
     $(INSTALLED_ANDROID_INFO_TXT_TARGET) \
     soong_docs
 
+# The droidcore target depends on the droidcore-unbundled subset and any other
+# targets for a non-unbundled (full source) full system build.
+.PHONY: droidcore
+droidcore: droidcore-unbundled
+
 # dist_files only for putting your library into the dist directory with a full build.
 .PHONY: dist_files
 
@@ -1709,21 +1715,43 @@
     $(apps_only_installed_files)))
 
 
-else ifeq (,$(TARGET_BUILD_UNBUNDLED))
+else ifeq ($(TARGET_BUILD_UNBUNDLED),$(TARGET_BUILD_UNBUNDLED_IMAGE))
+
+  # Truth table for entering this block of code:
+  # TARGET_BUILD_UNBUNDLED | TARGET_BUILD_UNBUNDLED_IMAGE | Action
+  # -----------------------|------------------------------|-------------------------
+  # not set                | not set                      | droidcore path
+  # not set                | true                         | invalid
+  # true                   | not set                      | skip
+  # true                   | true                         | droidcore-unbundled path
+
+  # We dist the following targets only for droidcore full build. These items
+  # can include java-related targets that would cause building framework java
+  # sources in a droidcore full build.
+
   $(call dist-for-goals, droidcore, \
+    $(BUILT_OTATOOLS_PACKAGE) \
+    $(APPCOMPAT_ZIP) \
+    $(DEXPREOPT_CONFIG_ZIP) \
+    $(DEXPREOPT_TOOLS_ZIP) \
+  )
+
+  # We dist the following targets for droidcore-unbundled (and droidcore since
+  # droidcore depends on droidcore-unbundled). The droidcore-unbundled target
+  # is a subset of droidcore. It can be used used for an unbundled build to
+  # avoid disting targets that would cause building framework java sources,
+  # which we want to avoid in an unbundled build.
+
+  $(call dist-for-goals, droidcore-unbundled, \
     $(INTERNAL_UPDATE_PACKAGE_TARGET) \
     $(INTERNAL_OTA_PACKAGE_TARGET) \
     $(INTERNAL_OTA_METADATA) \
     $(INTERNAL_OTA_PARTIAL_PACKAGE_TARGET) \
     $(INTERNAL_OTA_RETROFIT_DYNAMIC_PARTITIONS_PACKAGE_TARGET) \
-    $(BUILT_OTATOOLS_PACKAGE) \
     $(SYMBOLS_ZIP) \
     $(PROGUARD_DICT_ZIP) \
     $(PROGUARD_USAGE_ZIP) \
     $(COVERAGE_ZIP) \
-    $(APPCOMPAT_ZIP) \
-    $(DEXPREOPT_CONFIG_ZIP) \
-    $(DEXPREOPT_TOOLS_ZIP) \
     $(INSTALLED_FILES_FILE) \
     $(INSTALLED_FILES_JSON) \
     $(INSTALLED_FILES_FILE_VENDOR) \
@@ -1752,11 +1780,11 @@
     $(INSTALLED_ANDROID_INFO_TXT_TARGET) \
     $(INSTALLED_MISC_INFO_TARGET) \
     $(INSTALLED_RAMDISK_TARGET) \
-   )
+  )
 
   # Put a copy of the radio/bootloader files in the dist dir.
   $(foreach f,$(INSTALLED_RADIOIMAGE_TARGET), \
-    $(call dist-for-goals, droidcore, $(f)))
+    $(call dist-for-goals, droidcore-unbundled, $(f)))
 
   ifneq ($(ANDROID_BUILD_EMBEDDED),true)
     $(call dist-for-goals, droidcore, \
@@ -1765,13 +1793,13 @@
     )
   endif
 
-  $(call dist-for-goals, droidcore, \
+  $(call dist-for-goals, droidcore-unbundled, \
     $(INSTALLED_FILES_FILE_ROOT) \
     $(INSTALLED_FILES_JSON_ROOT) \
   )
 
   ifneq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
-    $(call dist-for-goals, droidcore, \
+    $(call dist-for-goals, droidcore-unbundled, \
       $(INSTALLED_FILES_FILE_RAMDISK) \
       $(INSTALLED_FILES_JSON_RAMDISK) \
       $(INSTALLED_FILES_FILE_DEBUG_RAMDISK) \
@@ -1791,7 +1819,7 @@
   endif
 
   ifeq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
-    $(call dist-for-goals, droidcore, \
+    $(call dist-for-goals, droidcore-unbundled, \
       $(recovery_ramdisk) \
     )
   endif
@@ -1821,10 +1849,25 @@
         $(call dist-for-goals,droidcore,$(f):ndk_apis/$(notdir $(f))))
   endif
 
-# Building a full system-- the default is to build droidcore
-droid_targets: droidcore dist_files
+  # For full system build (whether unbundled or not), we configure
+  # droid_targets to depend on droidcore-unbundled, which will set up the full
+  # system dependencies and also dist the subset of targets that correspond to
+  # an unbundled build (exclude building some framework sources).
 
-endif # !TARGET_BUILD_UNBUNDLED
+  droid_targets: droidcore-unbundled
+
+  ifeq (,$(TARGET_BUILD_UNBUNDLED_IMAGE))
+
+    # If we're building a full system (including the framework sources excluded
+    # by droidcore-unbundled), we configure droid_targets also to depend on
+    # droidcore, which includes all dist for droidcore, and will build the
+    # necessary framework sources.
+
+    droid_targets: droidcore dist_files
+
+  endif
+
+endif # TARGET_BUILD_UNBUNDLED == TARGET_BUILD_UNBUNDLED_IMAGE
 
 .PHONY: docs
 docs: $(ALL_DOCS)
diff --git a/core/tasks/collect_gpl_sources.mk b/core/tasks/collect_gpl_sources.mk
index ebc4181..9e9ab8e 100644
--- a/core/tasks/collect_gpl_sources.mk
+++ b/core/tasks/collect_gpl_sources.mk
@@ -26,4 +26,4 @@
 	$(hide) tar cfz $@ --exclude ".git*" $(PRIVATE_PATHS)
 
 # Dist the tgz only if we are doing a full build
-$(call dist-for-goals,droidcore,$(gpl_source_tgz))
+$(call dist-for-goals,droidcore-unbundled,$(gpl_source_tgz))
diff --git a/core/tasks/host_init_verifier.mk b/core/tasks/host_init_verifier.mk
index bdf996c..e463710 100644
--- a/core/tasks/host_init_verifier.mk
+++ b/core/tasks/host_init_verifier.mk
@@ -53,4 +53,4 @@
 		--out_product $(PRODUCT_OUT)/$(TARGET_COPY_OUT_PRODUCT) \
 		> $@
 
-$(call dist-for-goals,droidcore,$(host_init_verifier_output))
+$(call dist-for-goals,droidcore-unbundled,$(host_init_verifier_output))
diff --git a/core/tasks/module-info.mk b/core/tasks/module-info.mk
index c866259..c838264 100644
--- a/core/tasks/module-info.mk
+++ b/core/tasks/module-info.mk
@@ -26,7 +26,7 @@
 	$(hide) echo '}' >> $@
 
 
-droidcore: $(MODULE_INFO_JSON)
+droidcore-unbundled: $(MODULE_INFO_JSON)
 
 $(call dist-for-goals, general-tests, $(MODULE_INFO_JSON))
-$(call dist-for-goals, droidcore, $(MODULE_INFO_JSON))
+$(call dist-for-goals, droidcore-unbundled, $(MODULE_INFO_JSON))
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index f32ea76..28a5be1 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 := 2021-05-05
+      PLATFORM_SECURITY_PATCH := 2021-06-05
 endif
 .KATI_READONLY := PLATFORM_SECURITY_PATCH
 
diff --git a/target/board/Android.mk b/target/board/Android.mk
index 4dd6b17..142270e 100644
--- a/target/board/Android.mk
+++ b/target/board/Android.mk
@@ -24,8 +24,10 @@
 	$(call pretty,"Generated: ($@)")
 ifdef board_info_txt
 	$(hide) grep -v '#' $< > $@
-else
+else ifdef TARGET_BOOTLOADER_BOARD_NAME
 	$(hide) echo "board=$(TARGET_BOOTLOADER_BOARD_NAME)" > $@
+else
+	$(hide) echo "" > $@
 endif
 
 # Copy compatibility metadata to the device.
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 7e4c5ef..de3d63d 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -128,6 +128,7 @@
     libaudioeffect_jni \
     libbinder \
     libbinder_ndk \
+    libbinder_rpc_unstable \
     libc.bootstrap \
     libcamera2ndk \
     libcutils \
diff --git a/tools/signapk/OWNERS b/tools/signapk/OWNERS
index 0b8d398..23cab0b 100644
--- a/tools/signapk/OWNERS
+++ b/tools/signapk/OWNERS
@@ -1,2 +1,2 @@
 cbrubaker@google.com
-klyubin@google.com
+mpgroover@google.com