diff --git a/CleanSpec.mk b/CleanSpec.mk
index a1dec2e..6e7c9b0 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -299,11 +299,15 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
 
-# 5.0.1
+# API 22!
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
 
-# 5.0.2
+# 5.1!
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
 
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
diff --git a/core/Makefile b/core/Makefile
index d8d3044..15c7f02 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -200,6 +200,7 @@
 		echo "import /oem/oem.prop $(prop)" >> $@;)
 endif
 	$(hide) TARGET_BUILD_TYPE="$(TARGET_BUILD_VARIANT)" \
+			TARGET_BUILD_FLAVOR="$(TARGET_PRODUCT)-$(TARGET_BUILD_VARIANT)" \
 			TARGET_DEVICE="$(TARGET_DEVICE)" \
 			PRODUCT_NAME="$(TARGET_PRODUCT)" \
 			PRODUCT_BRAND="$(PRODUCT_BRAND)" \
@@ -491,6 +492,11 @@
 tmp_dir_for_image := $(call intermediates-dir-for,EXECUTABLES,boot_img)/bootimg
 INTERNAL_BOOTIMAGE_ARGS += --tmpdir $(tmp_dir_for_image)
 INTERNAL_BOOTIMAGE_ARGS += --genext2fs $(MKEXT2IMG)
+
+ifeq ($(TARGET_BOOTIMAGE_USE_EXTLINUX),true)
+INTERNAL_BOOTIMAGE_ARGS += --extlinuxconf $(TARGET_BOOTIMAGE_EXTLINUX_CONFIG)
+endif
+
 $(INSTALLED_BOOTIMAGE_TARGET): $(MKEXT2IMG) $(INTERNAL_BOOTIMAGE_FILES)
 	$(call pretty,"Target boot image: $@")
 	$(hide) $(MKEXT2BOOTIMG) $(INTERNAL_BOOTIMAGE_ARGS) --output $@
@@ -505,14 +511,14 @@
 $(INSTALLED_BOOTIMAGE_TARGET): $(MKBOOTIMG) $(INTERNAL_BOOTIMAGE_FILES) $(BOOT_SIGNER)
 	$(call pretty,"Target boot image: $@")
 	$(hide) $(MKBOOTIMG) $(INTERNAL_BOOTIMAGE_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $@
-	$(BOOT_SIGNER) /boot $@ $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY) $@
+	$(BOOT_SIGNER) /boot $@ $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY).pk8 $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY).x509.pem $@
 	$(hide) $(call assert-max-image-size,$@,$(BOARD_BOOTIMAGE_PARTITION_SIZE))
 
 .PHONY: bootimage-nodeps
 bootimage-nodeps: $(MKBOOTIMG) $(BOOT_SIGNER)
 	@echo "make $@: ignoring dependencies"
 	$(hide) $(MKBOOTIMG) $(INTERNAL_BOOTIMAGE_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $(INSTALLED_BOOTIMAGE_TARGET)
-	$(BOOT_SIGNER) /boot $(INSTALLED_BOOTIMAGE_TARGET) $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY) $(INSTALLED_BOOTIMAGE_TARGET)
+	$(BOOT_SIGNER) /boot $(INSTALLED_BOOTIMAGE_TARGET) $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY).pk8 $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY).x509.pem $(INSTALLED_BOOTIMAGE_TARGET)
 	$(hide) $(call assert-max-image-size,$(INSTALLED_BOOTIMAGE_TARGET),$(BOARD_BOOTIMAGE_PARTITION_SIZE))
 
 else # PRODUCT_SUPPORTS_VERITY != true
@@ -752,12 +758,8 @@
 # If PRODUCT_AAPT_PREF_CONFIG includes a dpi bucket, then use that value.
 recovery_density := $(filter %dpi,$(PRODUCT_AAPT_PREF_CONFIG))
 else
-# Otherwise, use the highest density that appears in PRODUCT_AAPT_CONFIG.
-# Order is important here; we'll take the first one that's found.
-recovery_densities := $(filter $(PRODUCT_AAPT_CONFIG_SP),xxxhdpi xxhdpi xhdpi hdpi tvdpi mdpi ldpi)
-ifneq (,$(recovery_densities))
-recovery_density := $(word 1,$(recovery_densities))
-endif
+# Otherwise, use the default medium density.
+recovery_densities := mdpi
 endif
 
 ifneq (,$(wildcard $(recovery_resources_common)-$(recovery_density)))
@@ -867,7 +869,7 @@
 	$(hide) $(MKBOOTFS) $(TARGET_RECOVERY_ROOT_OUT) | $(MINIGZIP) > $(recovery_ramdisk)
 	$(hide) $(MKBOOTIMG) $(INTERNAL_RECOVERYIMAGE_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $@
 ifeq (true,$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VERITY))
-	$(BOOT_SIGNER) /recovery $@ $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY) $@
+	$(BOOT_SIGNER) /recovery $@ $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY).pk8 $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VERITY_SIGNING_KEY).x509.pem $@
 endif
 	$(hide) $(call assert-max-image-size,$@,$(BOARD_RECOVERYIMAGE_PARTITION_SIZE))
 	@echo ----- Made recovery image: $@ --------
@@ -1240,6 +1242,12 @@
 endif # BOARD_VENDORIMAGE_FILE_SYSTEM_TYPE
 
 # -----------------------------------------------------------------
+# bring in the installer image generation defines if necessary
+ifeq ($(TARGET_USE_DISKINSTALLER),true)
+include bootable/diskinstaller/config.mk
+endif
+
+# -----------------------------------------------------------------
 # host tools needed to build dist and OTA packages
 
 DISTTOOLS :=  $(HOST_OUT_EXECUTABLES)/minigzip \
@@ -1421,6 +1429,7 @@
 	$(hide) echo "use_set_metadata=1" >> $(zip_root)/META/misc_info.txt
 	$(hide) echo "multistage_support=1" >> $(zip_root)/META/misc_info.txt
 	$(hide) echo "update_rename_support=1" >> $(zip_root)/META/misc_info.txt
+	$(hide) echo "blockimgdiff_versions=1,2" >> $(zip_root)/META/misc_info.txt
 ifneq ($(OEM_THUMBPRINT_PROPERTIES),)
 	# OTA scripts are only interested in fingerprint related properties
 	$(hide) echo "oem_fingerprint_properties=$(OEM_THUMBPRINT_PROPERTIES)" >> $(zip_root)/META/misc_info.txt
diff --git a/core/android_manifest.mk b/core/android_manifest.mk
index 21b95c2..c641b75 100644
--- a/core/android_manifest.mk
+++ b/core/android_manifest.mk
@@ -11,13 +11,27 @@
   full_android_manifest := $(LOCAL_PATH)/$(LOCAL_MANIFEST_FILE)
 endif
 
+my_full_libs_manifest_files := $(LOCAL_FULL_LIBS_MANIFEST_FILES)
+my_full_libs_manifest_deps := $(LOCAL_FULL_LIBS_MANIFEST_FILES)
+
+# Set up dependency on aar libraries
+ifdef LOCAL_STATIC_JAVA_AAR_LIBRARIES
+my_full_libs_manifest_deps += $(foreach lib, $(LOCAL_STATIC_JAVA_AAR_LIBRARIES),\
+  $(call intermediates-dir-for,JAVA_LIBRARIES,$(lib),,COMMON)/aar/classes.jar)
+my_full_libs_manifest_files += $(foreach lib, $(LOCAL_STATIC_JAVA_AAR_LIBRARIES),\
+  $(call intermediates-dir-for,JAVA_LIBRARIES,$(lib),,COMMON)/aar/AndroidManifest.xml)
+
+LOCAL_RESOURCE_DIR += $(foreach lib, $(LOCAL_STATIC_JAVA_AAR_LIBRARIES),\
+  $(call intermediates-dir-for,JAVA_LIBRARIES,$(lib),,COMMON)/aar/res)
+endif
+
 # Set up rules to merge library manifest files
-ifdef LOCAL_FULL_LIBS_MANIFEST_FILES
+ifdef my_full_libs_manifest_files
 main_android_manifest := $(full_android_manifest)
 full_android_manifest := $(intermediates.COMMON)/AndroidManifest.xml
-$(full_android_manifest): PRIVATE_LIBS_MANIFESTS := $(LOCAL_FULL_LIBS_MANIFEST_FILES)
-$(full_android_manifest) : $(main_android_manifest) $(LOCAL_FULL_LIBS_MANIFEST_FILES)
-	@echo "Merge android manifest files: $@ <-- $^"
+$(full_android_manifest): PRIVATE_LIBS_MANIFESTS := $(my_full_libs_manifest_files)
+$(full_android_manifest) : $(main_android_manifest) $(my_full_libs_manifest_deps)
+	@echo "Merge android manifest files: $@ <-- $< $(PRIVATE_LIBS_MANIFESTS)"
 	@mkdir -p $(dir $@)
 	$(hide) $(ANDROID_MANIFEST_MERGER) --main $< --libs $(PRIVATE_LIBS_MANIFESTS) \
 	    --out $@
diff --git a/core/apicheck_msg_current.txt b/core/apicheck_msg_current.txt
index 9abd381..440e7f8 100644
--- a/core/apicheck_msg_current.txt
+++ b/core/apicheck_msg_current.txt
@@ -7,7 +7,7 @@
       errors above.
 
    2) You can update current.txt by executing the following command:
-         make %UPDATE_API%
+         make update-api
 
       To submit the revised current.txt to the main Android repository,
       you will need approval.
diff --git a/core/base_rules.mk b/core/base_rules.mk
index ec3b59f..dfed3ea 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -116,6 +116,8 @@
     partition_tag := _VENDOR
   else ifeq (true,$(LOCAL_OEM_MODULE))
     partition_tag := _OEM
+  else ifeq (true,$(LOCAL_ODM_MODULE))
+    partition_tag := _ODM
   else
     # The definition of should-install-to-system will be different depending
     # on which goal (e.g., sdk or just droid) is being built.
diff --git a/core/binary.mk b/core/binary.mk
index d339317..1e313ff 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -184,9 +184,11 @@
 
 my_compiler_dependencies :=
 
-####################################################
+##################################################################
 ## Add FDO flags if FDO is turned on and supported
-####################################################
+## Please note that we will do option filtering during FDO build.
+## i.e. Os->O2, remove -fno-early-inline and -finline-limit.
+##################################################################
 ifeq ($(strip $(LOCAL_FDO_SUPPORT)), true)
   ifeq ($(strip $(LOCAL_IS_HOST_MODULE)),)
     my_cflags += $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_FDO_CFLAGS)
@@ -923,6 +925,21 @@
 my_ldflags := $(call $(LOCAL_2ND_ARCH_VAR_PREFIX)convert-to-$(my_host)clang-flags,$(my_ldflags))
 endif
 
+ifeq ($(LOCAL_FDO_SUPPORT), true)
+  build_with_fdo := false
+  ifeq ($(BUILD_FDO_INSTRUMENT), true)
+    build_with_fdo := true
+  endif
+  ifeq ($(BUILD_FDO_OPTIMIZE), true)
+    build_with_fdo := true
+  endif
+  ifeq ($(build_with_fdo), true)
+    my_cflags := $(patsubst -Os,-O2,$(my_cflags))
+    fdo_incompatible_flags=-fno-early-inlining -finline-limit=%
+    my_cflags := $(filter-out $(fdo_incompatible_flags),$(my_cflags))
+  endif
+endif
+
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_YACCFLAGS := $(LOCAL_YACCFLAGS)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_ASFLAGS := $(my_asflags)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_CONLYFLAGS := $(LOCAL_CONLYFLAGS)
diff --git a/core/cleanbuild.mk b/core/cleanbuild.mk
index 1bada38..cf980d8 100644
--- a/core/cleanbuild.mk
+++ b/core/cleanbuild.mk
@@ -132,23 +132,11 @@
 
 previous_build_config_file := $(PRODUCT_OUT)/previous_build_config.mk
 
-# TODO: this special case for the sdk is only necessary while "sdk"
-# is a valid make target.  Eventually, it will just be a product, at
-# which point TARGET_PRODUCT will handle it and we can avoid this check
-# of MAKECMDGOALS.  The "addprefix" is just to keep things pretty.
-ifneq ($(TARGET_PRODUCT),sdk)
-  building_sdk := $(addprefix -,$(filter sdk,$(MAKECMDGOALS)))
-else
-  # Don't bother with this extra part when explicitly building the sdk product.
-  building_sdk :=
-endif
-
 # A change in the list of aapt configs warrants an installclean, too.
 aapt_config_list := $(strip $(PRODUCT_AAPT_CONFIG) $(PRODUCT_AAPT_PREF_CONFIG))
 
 current_build_config := \
-    $(TARGET_PRODUCT)-$(TARGET_BUILD_VARIANT)$(building_sdk)-{$(aapt_config_list)}
-building_sdk :=
+    $(TARGET_PRODUCT)-$(TARGET_BUILD_VARIANT)-{$(aapt_config_list)}
 aapt_config_list :=
 force_installclean := false
 
@@ -220,6 +208,7 @@
 	$(PRODUCT_OUT)/obj/JAVA_LIBRARIES \
 	$(PRODUCT_OUT)/obj/FAKE \
 	$(PRODUCT_OUT)/obj/EXECUTABLES/adbd_intermediates \
+	$(PRODUCT_OUT)/obj/STATIC_LIBRARIES/libfs_mgr_intermediates \
 	$(PRODUCT_OUT)/obj/EXECUTABLES/init_intermediates \
 	$(PRODUCT_OUT)/obj/ETC/mac_permissions.xml_intermediates \
 	$(PRODUCT_OUT)/obj/ETC/sepolicy_intermediates \
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 92b3fc4..d5a5f03 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -30,6 +30,7 @@
 LOCAL_SRC_FILES:=
 LOCAL_PREBUILT_OBJ_FILES:=
 LOCAL_STATIC_JAVA_LIBRARIES:=
+LOCAL_STATIC_JAVA_AAR_LIBRARIES:=
 LOCAL_STATIC_LIBRARIES:=
 # Group static libraries with "-Wl,--start-group" and "-Wl,--end-group" when linking.
 LOCAL_GROUP_STATIC_LIBRARIES:=
@@ -130,6 +131,7 @@
 LOCAL_NO_CRT:=
 LOCAL_PROPRIETARY_MODULE:=
 LOCAL_OEM_MODULE:=
+LOCAL_ODM_MODULE:=
 LOCAL_PRIVILEGED_MODULE:=
 LOCAL_MODULE_OWNER:=
 LOCAL_CTS_TEST_PACKAGE:=
@@ -158,6 +160,8 @@
 LOCAL_MODULE_UNSUPPORTED_TARGET_ARCH:=
 LOCAL_MODULE_UNSUPPORTED_TARGET_ARCH_WARN:=
 LOCAL_MODULE_HOST_ARCH:=
+LOCAL_DPI_VARIANTS:=
+LOCAL_DPI_FILE_STEM:=
 
 # arch specific variables
 LOCAL_SRC_FILES_$(TARGET_ARCH):=
diff --git a/core/combo/HOST_darwin-x86.mk b/core/combo/HOST_darwin-x86.mk
index 4a2bfe3..ec37993 100644
--- a/core/combo/HOST_darwin-x86.mk
+++ b/core/combo/HOST_darwin-x86.mk
@@ -37,8 +37,8 @@
 ifneq (,$(strip $(wildcard $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)-gcc)))
 $(combo_2nd_arch_prefix)HOST_CC  := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)-gcc
 $(combo_2nd_arch_prefix)HOST_CXX := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_PREFIX)-g++
-ifeq ($(mac_sdk_version),10.8)
-# Mac SDK 10.8 no longer has stdarg.h, etc
+ifneq ($(filter 10.8 10.9, $(mac_sdk_version)),)
+# Mac SDK 10.8+ no longer has stdarg.h, etc
 host_toolchain_header := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_ROOT)/lib/gcc/i686-apple-darwin$(gcc_darwin_version)/4.2.1/include
 $(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += -isystem $(host_toolchain_header)
 endif
diff --git a/core/combo/HOST_darwin-x86_64.mk b/core/combo/HOST_darwin-x86_64.mk
index 0bc0227..a776a69 100644
--- a/core/combo/HOST_darwin-x86_64.mk
+++ b/core/combo/HOST_darwin-x86_64.mk
@@ -37,8 +37,8 @@
 ifneq (,$(strip $(wildcard $(HOST_TOOLCHAIN_PREFIX)-gcc)))
 HOST_CC  := $(HOST_TOOLCHAIN_PREFIX)-gcc
 HOST_CXX := $(HOST_TOOLCHAIN_PREFIX)-g++
-ifeq ($(mac_sdk_version),10.8)
-# Mac SDK 10.8 no longer has stdarg.h, etc
+ifneq ($(filter 10.8 10.9, $(mac_sdk_version)),)
+# Mac SDK 10.8+ no longer has stdarg.h, etc
 host_toolchain_header := $(HOST_TOOLCHAIN_ROOT)/lib/gcc/i686-apple-darwin$(gcc_darwin_version)/4.2.1/include
 HOST_GLOBAL_CFLAGS += -isystem $(host_toolchain_header)
 endif
diff --git a/core/combo/HOST_windows-x86.mk b/core/combo/HOST_windows-x86.mk
index fdb72a7..00e1974 100644
--- a/core/combo/HOST_windows-x86.mk
+++ b/core/combo/HOST_windows-x86.mk
@@ -27,7 +27,7 @@
 ifneq ($(strip $(USE_MINGW)),)
 HOST_ACP_UNAVAILABLE := true
 TOOLS_EXE_SUFFIX :=
-$(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += -DUSE_MINGW
+$(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += -DUSE_MINGW -DWIN32_LEAN_AND_MEAN
 $(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += -Wno-unused-parameter
 $(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += --sysroot=prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32
 $(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += -m32
diff --git a/core/combo/mac_version.mk b/core/combo/mac_version.mk
index b49feee..6defba7 100644
--- a/core/combo/mac_version.mk
+++ b/core/combo/mac_version.mk
@@ -9,7 +9,7 @@
 
 build_mac_version := $(shell sw_vers -productVersion)
 
-mac_sdk_versions_supported :=  10.6 10.7 10.8
+mac_sdk_versions_supported :=  10.6 10.7 10.8 10.9
 ifneq ($(strip $(MAC_SDK_VERSION)),)
 mac_sdk_version := $(MAC_SDK_VERSION)
 ifeq ($(filter $(mac_sdk_version),$(mac_sdk_versions_supported)),)
diff --git a/core/dex_preopt_libart.mk b/core/dex_preopt_libart.mk
index de995b7..cfbf221 100644
--- a/core/dex_preopt_libart.mk
+++ b/core/dex_preopt_libart.mk
@@ -16,7 +16,9 @@
 DEX2OATD_DEPENDENCY := $(DEX2OAT_DEPENDENCY)
 DEX2OATD_DEPENDENCY += $(DEX2OATD)
 
-PRELOADED_CLASSES := frameworks/base/preloaded-classes
+# Use the first preloaded-classes file in PRODUCT_COPY_FILES.
+PRELOADED_CLASSES := $(call word-colon,1,$(firstword \
+    $(filter %system/etc/preloaded-classes,$(PRODUCT_COPY_FILES))))
 
 # Use the first compiled-classes file in PRODUCT_COPY_FILES.
 COMPILED_CLASSES := $(call word-colon,1,$(firstword \
diff --git a/core/dpi_specific_apk.mk b/core/dpi_specific_apk.mk
new file mode 100644
index 0000000..0e8cbdf
--- /dev/null
+++ b/core/dpi_specific_apk.mk
@@ -0,0 +1,70 @@
+# Set up rules to build dpi-specific apk, with whatever else from the base apk.
+# Input variable: my_dpi, and all other variables set up in package_internal.mk.
+#
+
+dpi_apk_name := $(LOCAL_MODULE)_$(my_dpi)
+dpi_intermediate := $(call intermediates-dir-for,APPS,$(dpi_apk_name))
+built_dpi_apk := $(dpi_intermediate)/package.apk
+
+# Set up all the target-specific variables.
+$(built_dpi_apk): PRIVATE_MODULE := $(dpi_apk_name)
+$(built_dpi_apk): PRIVATE_AAPT_FLAGS := $(LOCAL_AAPT_FLAGS) $(PRODUCT_AAPT_FLAGS) $($(LOCAL_PACKAGE_NAME)_aapt_flags_$(my_dpi))
+# Clear PRIVATE_PRODUCT_AAPT_CONFIG to include everything by default.
+$(built_dpi_apk): PRIVATE_PRODUCT_AAPT_CONFIG :=
+$(built_dpi_apk): PRIVATE_PRODUCT_AAPT_PREF_CONFIG := $(my_dpi)
+$(built_dpi_apk): PRIVATE_ANDROID_MANIFEST := $(full_android_manifest)
+$(built_dpi_apk): PRIVATE_RESOURCE_DIR := $(LOCAL_RESOURCE_DIR)
+$(built_dpi_apk): PRIVATE_ASSET_DIR := $(LOCAL_ASSET_DIR)
+$(built_dpi_apk): PRIVATE_AAPT_INCLUDES := $(all_library_res_package_exports)
+ifneq (,$(filter-out current system_current, $(LOCAL_SDK_VERSION)))
+$(built_dpi_apk): PRIVATE_DEFAULT_APP_TARGET_SDK := $(LOCAL_SDK_VERSION)
+else
+$(built_dpi_apk): PRIVATE_DEFAULT_APP_TARGET_SDK := $(DEFAULT_APP_TARGET_SDK)
+endif
+$(built_dpi_apk): PRIVATE_MANIFEST_PACKAGE_NAME := $(LOCAL_MANIFEST_PACKAGE_NAME)
+$(built_dpi_apk): PRIVATE_MANIFEST_INSTRUMENTATION_FOR := $(LOCAL_INSTRUMENTATION_FOR)
+$(built_dpi_apk): PRIVATE_JNI_SHARED_LIBRARIES := $(jni_shared_libraries_with_abis)
+$(built_dpi_apk): PRIVATE_JNI_SHARED_LIBRARIES_ABI := $(jni_shared_libraries_abis)
+$(built_dpi_apk): PRIVATE_DEX_FILE := $(built_dex)
+# Note that PRIVATE_CLASS_INTERMEDIATES_DIR points to the base apk's intermediate dir.
+$(built_dpi_apk): PRIVATE_CLASS_INTERMEDIATES_DIR := $(intermediates)/classes
+$(built_dpi_apk): PRIVATE_EXTRA_JAR_ARGS := $(extra_jar_args)
+$(built_dpi_apk): PRIVATE_PRIVATE_KEY := $(private_key)
+$(built_dpi_apk): PRIVATE_CERTIFICATE := $(certificate)
+$(built_dpi_apk): PRIVATE_ADDITIONAL_CERTIFICATES := $(foreach c,\
+    $(LOCAL_ADDITIONAL_CERTIFICATES), $(c).x509.pem $(c).pk8)
+
+# Set up dependenncies and the build recipe.
+$(built_dpi_apk) : $(R_file_stamp)
+$(built_dpi_apk) : $(all_library_res_package_export_deps)
+$(built_dpi_apk) : $(built_dex)
+$(built_dpi_apk) : $(private_key) $(certificate) $(SIGNAPK_JAR)
+$(built_dpi_apk) : $(AAPT) | $(ZIPALIGN)
+$(built_dpi_apk) : $(all_res_assets) $(jni_shared_libraries) $(full_android_manifest)
+	@echo "target Package: $(PRIVATE_MODULE) ($@)"
+	$(create-empty-package)
+	$(add-assets-to-package)
+ifneq ($(jni_shared_libraries),)
+	$(add-jni-shared-libs-to-package)
+endif
+ifneq ($(full_classes_jar),)
+	$(add-dex-to-package)
+endif
+	$(add-carried-java-resources)
+ifneq ($(extra_jar_args),)
+	$(add-java-resources-to-package)
+endif
+	$(sign-package)
+	$(align-package)
+
+# Set up global variables to register this apk to the higher-level dependency graph.
+ALL_MODULES += $(dpi_apk_name)
+ALL_MODULES.$(dpi_apk_name).CLASS := APPS
+ALL_MODULES.$(dpi_apk_name).BUILT := $(built_dpi_apk)
+PACKAGES := $(PACKAGES) $(dpi_apk_name)
+PACKAGES.$(dpi_apk_name).PRIVATE_KEY := $(private_key)
+PACKAGES.$(dpi_apk_name).CERTIFICATE := $(certificate)
+
+# Phony targets used by "apps_only".
+.PHONY: $(dpi_apk_name)
+$(dpi_apk_name) : $(built_dpi_apk)
diff --git a/core/dynamic_binary.mk b/core/dynamic_binary.mk
index 3d6ad4a..08fb176 100644
--- a/core/dynamic_binary.mk
+++ b/core/dynamic_binary.mk
@@ -17,16 +17,13 @@
 # know its results before base_rules.mk is included.
 include $(BUILD_SYSTEM)/configure_module_stem.mk
 
-# base_rules.make defines $(intermediates), but we need its value
-# before we include base_rules.  Make a guess, and verify that
-# it's correct once the real value is defined.
-guessed_intermediates := $(call local-intermediates-dir,,$(LOCAL_2ND_ARCH_VAR_PREFIX))
+intermediates := $(call local-intermediates-dir,,$(LOCAL_2ND_ARCH_VAR_PREFIX))
 
 # Define the target that is the unmodified output of the linker.
 # The basename of this target must be the same as the final output
 # binary name, because it's used to set the "soname" in the binary.
 # The includer of this file will define a rule to build this target.
-linked_module := $(guessed_intermediates)/LINKED/$(my_built_module_stem)
+linked_module := $(intermediates)/LINKED/$(my_built_module_stem)
 
 ALL_ORIGINAL_DYNAMIC_BINARIES += $(linked_module)
 
@@ -41,11 +38,6 @@
 include $(BUILD_SYSTEM)/binary.mk
 ###################################
 
-# Make sure that our guess at the value of intermediates was correct.
-ifneq ($(intermediates),$(guessed_intermediates))
-$(error Internal error: guessed path '$(guessed_intermediates)' doesn't match '$(intermediates))
-endif
-
 ###########################################################
 ## Compress
 ###########################################################
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 124a91b..ad78be3 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -120,6 +120,7 @@
 TARGET_COPY_OUT_SYSTEM := system
 TARGET_COPY_OUT_DATA := data
 TARGET_COPY_OUT_OEM := oem
+TARGET_COPY_OUT_ODM := odm
 TARGET_COPY_OUT_ROOT := root
 TARGET_COPY_OUT_RECOVERY := recovery
 ###########################################
@@ -343,7 +344,7 @@
 
 TARGET_OUT_OEM := $(PRODUCT_OUT)/$(TARGET_COPY_OUT_OEM)
 TARGET_OUT_OEM_EXECUTABLES := $(TARGET_OUT_OEM)/bin
-ifneq ($(filter %64,$(TARGET_ARCH)),)
+ifeq ($(TARGET_IS_64_BIT),true)
 TARGET_OUT_OEM_SHARED_LIBRARIES := $(TARGET_OUT_OEM)/lib64
 else
 TARGET_OUT_OEM_SHARED_LIBRARIES := $(TARGET_OUT_OEM)/lib
@@ -357,6 +358,20 @@
 $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_OUT_OEM_SHARED_LIBRARIES := $(TARGET_OUT_OEM)/lib
 $(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_OUT_OEM_APPS := $(TARGET_OUT_OEM_APPS)
 
+TARGET_OUT_ODM := $(PRODUCT_OUT)/$(TARGET_COPY_OUT_ODM)
+TARGET_OUT_ODM_EXECUTABLES := $(TARGET_OUT_ODM)/bin
+ifeq ($(TARGET_IS_64_BIT),true)
+TARGET_OUT_ODM_SHARED_LIBRARIES := $(TARGET_OUT_ODM)/lib64
+else
+TARGET_OUT_ODM_SHARED_LIBRARIES := $(TARGET_OUT_ODM)/lib
+endif
+TARGET_OUT_ODM_APPS := $(TARGET_OUT_ODM)/app
+TARGET_OUT_ODM_ETC := $(TARGET_OUT_ODM)/etc
+
+$(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_OUT_ODM_EXECUTABLES := $(TARGET_OUT_ODM_EXECUTABLES)
+$(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_OUT_ODM_SHARED_LIBRARIES := $(TARGET_OUT_ODM)/lib
+$(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_OUT_ODM_APPS := $(TARGET_OUT_ODM_APPS)
+
 TARGET_OUT_UNSTRIPPED := $(PRODUCT_OUT)/symbols
 TARGET_OUT_EXECUTABLES_UNSTRIPPED := $(TARGET_OUT_UNSTRIPPED)/system/bin
 TARGET_OUT_SHARED_LIBRARIES_UNSTRIPPED := $(TARGET_OUT_UNSTRIPPED)/system/lib
diff --git a/core/install_jni_libs_internal.mk b/core/install_jni_libs_internal.mk
index 944420b..c28bb15 100644
--- a/core/install_jni_libs_internal.mk
+++ b/core/install_jni_libs_internal.mk
@@ -100,9 +100,15 @@
 my_prebuilt_jni_libs := $(addprefix $(LOCAL_PATH)/, \
     $(filter-out @%, $(my_prebuilt_jni_libs)))
 ifdef my_prebuilt_jni_libs
+ifdef my_embed_jni
+# Embed my_prebuilt_jni_libs to the apk
+my_jni_shared_libraries += $(my_prebuilt_jni_libs)
+else # not my_embed_jni
+# Install my_prebuilt_jni_libs as separate files.
 $(foreach lib, $(my_prebuilt_jni_libs), \
     $(eval $(call copy-one-file, $(lib), $(my_app_lib_path)/$(notdir $(lib)))))
 
 $(LOCAL_INSTALLED_MODULE) : | $(addprefix $(my_app_lib_path)/, $(notdir $(my_prebuilt_jni_libs)))
+endif  # my_embed_jni
 endif  # inner my_prebuilt_jni_libs
 endif  # outer my_prebuilt_jni_libs
diff --git a/core/java.mk b/core/java.mk
index debdf53..a969254 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -52,6 +52,9 @@
 endif
 endif
 
+# LOCAL_STATIC_JAVA_AAR_LIBRARIES are special LOCAL_STATIC_JAVA_LIBRARIES
+LOCAL_STATIC_JAVA_LIBRARIES := $(strip $(LOCAL_STATIC_JAVA_LIBRARIES) $(LOCAL_STATIC_JAVA_AAR_LIBRARIES))
+
 LOCAL_JAVA_LIBRARIES := $(sort $(LOCAL_JAVA_LIBRARIES))
 
 LOCAL_BUILT_MODULE_STEM := $(strip $(LOCAL_BUILT_MODULE_STEM))
diff --git a/core/package_internal.mk b/core/package_internal.mk
index bb458d4..a6ad354 100644
--- a/core/package_internal.mk
+++ b/core/package_internal.mk
@@ -123,7 +123,8 @@
 
 all_res_assets := $(strip $(all_assets) $(all_resources))
 
-package_expected_intermediates_COMMON := $(call local-intermediates-dir,COMMON)
+intermediates.COMMON := $(call local-intermediates-dir,COMMON)
+
 # If no assets or resources were found, clear the directory variables so
 # we don't try to build them.
 ifneq (true,$(need_compile_asset))
@@ -136,7 +137,7 @@
 # Make sure that R_file_stamp inherits the proper PRIVATE vars.
 # If R.stamp moves, be sure to update the framework makefile,
 # which has intimate knowledge of its location.
-R_file_stamp := $(package_expected_intermediates_COMMON)/src/R.stamp
+R_file_stamp := $(intermediates.COMMON)/src/R.stamp
 LOCAL_INTERMEDIATE_TARGETS += $(R_file_stamp)
 endif
 
@@ -156,7 +157,7 @@
 proguard_options_file :=
 ifneq ($(LOCAL_PROGUARD_ENABLED),custom)
 ifeq ($(need_compile_res),true)
-    proguard_options_file := $(package_expected_intermediates_COMMON)/proguard_options
+    proguard_options_file := $(intermediates.COMMON)/proguard_options
 endif # need_compile_res
 endif # !custom
 LOCAL_PROGUARD_FLAGS := $(addprefix -include ,$(proguard_options_file)) $(LOCAL_PROGUARD_FLAGS)
@@ -192,6 +193,8 @@
 
 rs_compatibility_jni_libs :=
 
+include $(BUILD_SYSTEM)/android_manifest.mk
+
 #################################
 include $(BUILD_SYSTEM)/java.mk
 #################################
@@ -201,8 +204,6 @@
   LOCAL_SDK_RES_VERSION:=$(LOCAL_SDK_VERSION)
 endif
 
-include $(BUILD_SYSTEM)/android_manifest.mk
-
 $(LOCAL_INTERMEDIATE_TARGETS): \
     PRIVATE_ANDROID_MANIFEST := $(full_android_manifest)
 ifneq (,$(filter-out current system_current, $(LOCAL_SDK_VERSION)))
@@ -223,11 +224,6 @@
 # At the same time, this will copy the R.java file to a central
 # 'R' directory to make it easier to add the files to an IDE.
 #
-#TODO: use PRIVATE_SOURCE_INTERMEDIATES_DIR instead of
-#      $(intermediates.COMMON)/src
-ifneq ($(package_expected_intermediates_COMMON),$(intermediates.COMMON))
-  $(error $(LOCAL_MODULE): internal error: expected intermediates.COMMON "$(package_expected_intermediates_COMMON)" != intermediates.COMMON "$(intermediates.COMMON)")
-endif
 
 $(R_file_stamp): PRIVATE_RESOURCE_PUBLICS_OUTPUT := \
 			$(intermediates.COMMON)/public_resources.xml
@@ -407,6 +403,16 @@
 	$(align-package)
 
 ###############################
+## Build dpi-specific apks, if it's apps_only build.
+ifdef TARGET_BUILD_APPS
+ifdef LOCAL_DPI_VARIANTS
+$(foreach d, $(LOCAL_DPI_VARIANTS), \
+  $(eval my_dpi := $(d)) \
+  $(eval include $(BUILD_SYSTEM)/dpi_specific_apk.mk))
+endif
+endif
+
+###############################
 ## Rule to build the odex file
 ifdef LOCAL_DEX_PREOPT
 $(built_odex): PRIVATE_DEX_FILE := $(built_dex)
diff --git a/core/prebuilt_internal.mk b/core/prebuilt_internal.mk
index 284884c..bc6088f 100644
--- a/core/prebuilt_internal.mk
+++ b/core/prebuilt_internal.mk
@@ -114,6 +114,19 @@
 ifeq ($(LOCAL_MODULE_CLASS),APPS)
 PACKAGES.$(LOCAL_MODULE).OVERRIDES := $(strip $(LOCAL_OVERRIDES_PACKAGES))
 
+# Select dpi-specific source
+ifdef LOCAL_DPI_VARIANTS
+my_dpi := $(firstword $(filter $(LOCAL_DPI_VARIANTS),$(PRODUCT_AAPT_PREF_CONFIG) $(PRODUCT_AAPT_PREBUILT_DPI)))
+ifdef my_dpi
+ifdef LOCAL_DPI_FILE_STEM
+my_prebuilt_dpi_file_stem := $(LOCAL_DPI_FILE_STEM)
+else
+my_prebuilt_dpi_file_stem := $(LOCAL_MODULE)_%.apk
+endif
+my_prebuilt_src_file := $(dir $(my_prebuilt_src_file))$(subst %,$(my_dpi),$(my_prebuilt_dpi_file_stem))
+endif  # my_dpi
+endif  # LOCAL_DPI_VARIANTS
+
 rs_compatibility_jni_libs :=
 include $(BUILD_SYSTEM)/install_jni_libs.mk
 
@@ -247,10 +260,26 @@
 # while the deps should be in the common dir, so we make a copy in the common dir.
 # For nonstatic library, $(common_javalib_jar) is the dependency file,
 # while $(common_classes_jar) is used to link.
-common_classes_jar := $(call intermediates-dir-for,JAVA_LIBRARIES,$(LOCAL_MODULE),,COMMON)/classes.jar
-common_javalib_jar := $(dir $(common_classes_jar))javalib.jar
+common_classes_jar := $(intermediates.COMMON)/classes.jar
+common_javalib_jar := $(intermediates.COMMON)/javalib.jar
 
-$(common_classes_jar) : $(my_prebuilt_src_file) | $(ACP)
+$(common_classes_jar) $(common_javalib_jar): PRIVATE_MODULE := $(LOCAL_MODULE)
+
+ifneq ($(filter %.aar, $(my_prebuilt_src_file)),)
+# This is .aar file, archive of classes.jar and Android resources.
+my_src_jar := $(intermediates.COMMON)/aar/classes.jar
+
+$(my_src_jar) : $(my_prebuilt_src_file)
+	$(hide) rm -rf $(dir $@) && mkdir -p $(dir $@)
+	$(hide) unzip -qo -d $(dir $@) $<
+	# Make sure the extracted classes.jar has a new timestamp.
+	$(hide) touch $@
+
+else
+# This is jar file.
+my_src_jar := $(my_prebuilt_src_file)
+endif
+$(common_classes_jar) : $(my_src_jar) | $(ACP)
 	$(transform-prebuilt-to-target)
 
 $(common_javalib_jar) : $(common_classes_jar) | $(ACP)
diff --git a/core/product.mk b/core/product.mk
index ed906cb..f0fc921 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -70,6 +70,7 @@
     PRODUCT_LOCALES \
     PRODUCT_AAPT_CONFIG \
     PRODUCT_AAPT_PREF_CONFIG \
+    PRODUCT_AAPT_PREBUILT_DPI \
     PRODUCT_PACKAGES \
     PRODUCT_PACKAGES_DEBUG \
     PRODUCT_PACKAGES_ENG \
diff --git a/core/product_config.mk b/core/product_config.mk
index d4ba364..e7fa75e 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -304,19 +304,9 @@
 endif
 
 # Add PRODUCT_LOCALES to PRODUCT_AAPT_CONFIG
-PRODUCT_AAPT_CONFIG := $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_AAPT_CONFIG))
-PRODUCT_AAPT_CONFIG := $(PRODUCT_LOCALES) $(PRODUCT_AAPT_CONFIG)
+PRODUCT_AAPT_CONFIG := $(strip $(PRODUCT_LOCALES) $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_AAPT_CONFIG))
 PRODUCT_AAPT_PREF_CONFIG := $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_AAPT_PREF_CONFIG))
-
-# Default to medium-density assets.
-# (Can be overridden in the device config, e.g.: PRODUCT_AAPT_CONFIG += hdpi)
-PRODUCT_AAPT_CONFIG := $(strip \
-    $(PRODUCT_AAPT_CONFIG) \
-    $(if $(filter %dpi,$(PRODUCT_AAPT_CONFIG)),,mdpi))
-PRODUCT_AAPT_PREF_CONFIG := $(strip $(PRODUCT_AAPT_PREF_CONFIG))
-
-# Everyone gets nodpi and anydpi assets which are density-independent.
-PRODUCT_AAPT_CONFIG += nodpi anydpi
+PRODUCT_AAPT_PREBUILT_DPI := $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_AAPT_PREBUILT_DPI))
 
 # Keep a copy of the space-separated config
 PRODUCT_AAPT_CONFIG_SP := $(PRODUCT_AAPT_CONFIG)
@@ -324,8 +314,6 @@
 # Convert spaces to commas.
 PRODUCT_AAPT_CONFIG := \
     $(subst $(space),$(comma),$(strip $(PRODUCT_AAPT_CONFIG)))
-PRODUCT_AAPT_PREF_CONFIG := \
-    $(subst $(space),$(comma),$(strip $(PRODUCT_AAPT_PREF_CONFIG)))
 
 # product-scoped aapt flags
 PRODUCT_AAPT_FLAGS :=
diff --git a/core/tasks/apicheck.mk b/core/tasks/apicheck.mk
index fc98f5b..683a075 100644
--- a/core/tasks/apicheck.mk
+++ b/core/tasks/apicheck.mk
@@ -31,6 +31,11 @@
              )\
         ))
 
+.PHONY: check-public-api
+checkapi : check-public-api
+
+.PHONY: update-api
+
 # INTERNAL_PLATFORM_API_FILE is the one build by droiddoc.
 # Note that since INTERNAL_PLATFORM_API_FILE is the byproduct of api-stubs module,
 # (See frameworks/base/Android.mk)
@@ -39,7 +44,7 @@
 # Check that the API we're building hasn't broken the last-released
 # SDK version.
 $(eval $(call check-api, \
-    checkapi-last, \
+    checkpublicapi-last, \
     $(SRC_API_DIR)/$(last_released_sdk_version).txt, \
     $(INTERNAL_PLATFORM_API_FILE), \
     frameworks/base/api/removed.txt, \
@@ -48,14 +53,14 @@
     -error 7 -error 8 -error 9 -error 10 -error 11 -error 12 -error 13 -error 14 -error 15 \
     -error 16 -error 17 -error 18 , \
     cat $(BUILD_SYSTEM)/apicheck_msg_last.txt, \
-    checkapi, \
+    check-public-api, \
     $(call doc-timestamp-for,api-stubs) \
     ))
 
 # Check that the API we're building hasn't changed from the not-yet-released
 # SDK version.
 $(eval $(call check-api, \
-    checkapi-current, \
+    checkpublicapi-current, \
     frameworks/base/api/current.txt, \
     $(INTERNAL_PLATFORM_API_FILE), \
     frameworks/base/api/removed.txt, \
@@ -64,21 +69,23 @@
     -error 7 -error 8 -error 9 -error 10 -error 11 -error 12 -error 13 -error 14 -error 15 \
     -error 16 -error 17 -error 18 -error 19 -error 20 -error 21 -error 23 -error 24 \
     -error 25 -error 26 -error 27, \
-    sed -e 's/%UPDATE_API%/update-api/g' $(BUILD_SYSTEM)/apicheck_msg_current.txt, \
-    checkapi, \
+    cat $(BUILD_SYSTEM)/apicheck_msg_current.txt, \
+    check-public-api, \
     $(call doc-timestamp-for,api-stubs) \
     ))
 
-.PHONY: update-api
-update-api: $(INTERNAL_PLATFORM_API_FILE) | $(ACP)
+.PHONY: update-public-api
+update-public-api: $(INTERNAL_PLATFORM_API_FILE) | $(ACP)
 	@echo Copying current.txt
 	$(hide) $(ACP) $(INTERNAL_PLATFORM_API_FILE) frameworks/base/api/current.txt
 	@echo Copying removed.txt
 	$(hide) $(ACP) $(INTERNAL_PLATFORM_REMOVED_API_FILE) frameworks/base/api/removed.txt
 
+update-api : update-public-api
 
 #####################Check System API#####################
-.PHONY: checksystemapi
+.PHONY: check-system-api
+checkapi : check-system-api
 
 # Check that the System API we're building hasn't broken the last-released
 # SDK version.
@@ -92,7 +99,7 @@
     -error 7 -error 8 -error 9 -error 10 -error 11 -error 12 -error 13 -error 14 -error 15 \
     -error 16 -error 17 -error 18 , \
     cat $(BUILD_SYSTEM)/apicheck_msg_last.txt, \
-    checksystemapi, \
+    check-system-api, \
     $(call doc-timestamp-for,system-api-stubs) \
     ))
 
@@ -108,12 +115,14 @@
     -error 7 -error 8 -error 9 -error 10 -error 11 -error 12 -error 13 -error 14 -error 15 \
     -error 16 -error 17 -error 18 -error 19 -error 20 -error 21 -error 23 -error 24 \
     -error 25 -error 26 -error 27, \
-    sed -e 's/%UPDATE_API%/update-system-api/g' $(BUILD_SYSTEM)/apicheck_msg_current.txt, \
-    checksystemapi, \
+    cat $(BUILD_SYSTEM)/apicheck_msg_current.txt, \
+    check-system-api, \
     $(call doc-timestamp-for,system-api-stubs) \
     ))
 
 .PHONY: update-system-api
+update-api : update-system-api
+
 update-system-api: $(INTERNAL_PLATFORM_SYSTEM_API_FILE) | $(ACP)
 	@echo Copying system-current.txt
 	$(hide) $(ACP) $(INTERNAL_PLATFORM_SYSTEM_API_FILE) frameworks/base/api/system-current.txt
diff --git a/core/tasks/build_custom_images.mk b/core/tasks/build_custom_images.mk
new file mode 100644
index 0000000..263b81a
--- /dev/null
+++ b/core/tasks/build_custom_images.mk
@@ -0,0 +1,58 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Build additional images requested by the product makefile.
+# This script gives the ability to build multiple additional images and you can
+# configure what modules/files to include in each image.
+# 1. Define PRODUCT_CUSTOM_IMAGE_MAKEFILES in your product makefile.
+#    PRODUCT_CUSTOM_IMAGE_MAKEFILES is a list of makefiles.
+#    Each makefile configures an image.
+#    For image configuration makefile foo/bar/xyz.mk, the built image file name
+#    will be xyz.img. So make sure they won't conflict.
+# 2. In each image's configuration makefile, you can define variables:
+#   - CUSTOM_IMAGE_MOUNT_POINT, the mount point, such as "oem", "odm" etc.
+#   - CUSTOM_IMAGE_PARTITION_SIZE
+#   - CUSTOM_IMAGE_FILE_SYSTEM_TYPE
+#   - CUSTOM_IMAGE_DICT_FILE, a text file defines a dictionary accepted by
+#     BuildImage() in tools/releasetools/build_image.py.
+#   - CUSTOM_IMAGE_MODULES, a list of module names you want to include in
+#     the image; Not only the module itself will be installed to proper path in
+#     the image, you can also piggyback additional files/directories with the
+#     module's LOCAL_PICKUP_FILES.
+#   - CUSTOM_IMAGE_COPY_FILES, a list of "<src>:<dest>" to be copied to the
+#     image. <dest> is relativ to the root of the image.
+#
+# To build all those images, run "make custom_images".
+
+ifneq ($(filter $(MAKECMDGOALS),custom_images),)
+
+.PHONY: custom_images
+
+custom_image_parameter_variables := \
+  CUSTOM_IMAGE_MOUNT_POINT \
+  CUSTOM_IMAGE_PARTITION_SIZE \
+  CUSTOM_IMAGE_FILE_SYSTEM_TYPE \
+  CUSTOM_IMAGE_DICT_FILE \
+  CUSTOM_IMAGE_MODULES \
+  CUSTOM_IMAGE_COPY_FILES \
+
+# We don't expect product makefile to inherit/override PRODUCT_CUSTOM_IMAGE_MAKEFILES,
+# so we don't put it in the _product_var_list.
+$(foreach mk, $(PRODUCT_CUSTOM_IMAGE_MAKEFILES),\
+  $(eval my_custom_imag_makefile := $(mk))\
+  $(eval include $(BUILD_SYSTEM)/tasks/tools/build_custom_image.mk))
+
+endif
diff --git a/core/tasks/factory_bundle.mk b/core/tasks/factory_bundle.mk
index 054a52a..51531cb 100644
--- a/core/tasks/factory_bundle.mk
+++ b/core/tasks/factory_bundle.mk
@@ -46,7 +46,7 @@
     $(eval _fb_m_name := $(word 1,$(_fb_m_tuple))) \
     $(eval _fb_dests := $(wordlist 2,999,$(_fb_m_tuple))) \
     $(eval _fb_m_built := $(filter $(HOST_OUT)/%, $(ALL_MODULES.$(_fb_m_name).BUILT))) \
-    $(if $(_fb_m_built),,$(error no built file in requested_modules for '$(_fb_m_built)'))\
+    $(if $(_fb_m_built),,$(warning no built file in requested_modules for '$(_fb_m_built)'))\
     $(foreach _fb_f,$(_fb_dests),$(eval $(call copy-one-file,$(_fb_m_built),$(root_dir)/$(_fb_f))))\
     $(addprefix $(root_dir)/,$(_fb_dests)) \
     )) \
@@ -82,4 +82,3 @@
 
 endif # TARGET_BUILD_PDK
 endif # ONE_SHOT_MAKEFILE
-
diff --git a/core/tasks/factory_ramdisk.mk b/core/tasks/factory_ramdisk.mk
index 00fcdde..d65d931 100644
--- a/core/tasks/factory_ramdisk.mk
+++ b/core/tasks/factory_ramdisk.mk
@@ -44,7 +44,7 @@
     $(eval _fulldest := $(TARGET_FACTORY_RAMDISK_OUT)/$(1)) \
     $(eval $(call copy-one-file,$(_iofrm_src),$(_fulldest))) \
     $(eval INTERNAL_FACTORY_RAMDISK_EXTRA_MODULES_FILES += $(_fulldest)), \
-    $(error Error: Cannot find match in "$(2)" for "$(1)") \
+    $(warning Warning: Cannot find built file in "$(2)" for "$(1)") \
     )
 endef
 
diff --git a/core/tasks/tools/build_custom_image.mk b/core/tasks/tools/build_custom_image.mk
new file mode 100644
index 0000000..fa9cda2
--- /dev/null
+++ b/core/tasks/tools/build_custom_image.mk
@@ -0,0 +1,105 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+# Define rule to build one custom image.
+# Input variables: my_custom_imag_makefile
+
+$(call clear-var-list, $(custom_image_parameter_variables))
+
+include $(my_custom_imag_makefile)
+
+my_custom_image_name := $(basename $(notdir $(my_custom_imag_makefile)))
+
+intermediates := $(call intermediates-dir-for,PACKAGING,$(my_custom_image_name))
+my_built_custom_image := $(intermediates)/$(my_custom_image_name).img
+my_staging_dir := $(intermediates)/$(my_custom_image_name)
+
+# Collect CUSTOM_IMAGE_MODULES's installd files and their PICKUP_FILES.
+my_built_modules :=
+my_copy_pairs :=
+my_pickup_files :=
+
+$(foreach m,$(CUSTOM_IMAGE_MODULES),\
+  $(eval _pickup_files := $(strip $(ALL_MODULES.$(m).PICKUP_FILES)\
+    $(ALL_MODULES.$(m)$(TARGET_2ND_ARCH_MODULE_SUFFIX).PICKUP_FILES)))\
+  $(eval _built_files := $(strip $(ALL_MODULES.$(m).BUILT_INSTALLED)\
+    $(ALL_MODULES.$(m)$(TARGET_2ND_ARCH_MODULE_SUFFIX).BUILT_INSTALLED)))\
+  $(if $(_pickup_files)$(_built_files),,\
+    $(warning Unknown installed file for module '$(m)'))\
+  $(eval my_pickup_files += $(_pickup_files))\
+  $(foreach i, $(_built_files),\
+    $(eval bui_ins := $(subst :,$(space),$(i)))\
+    $(eval ins := $(word 2,$(bui_ins)))\
+    $(if $(filter $(TARGET_OUT_ROOT)/%,$(ins)),\
+      $(eval bui := $(word 1,$(bui_ins)))\
+      $(eval my_built_modules += $(bui))\
+      $(eval my_copy_dest := $(patsubst $(PRODUCT_OUT)/%,%,$(ins)))\
+      $(eval my_copy_dest := $(subst /,$(space),$(my_copy_dest)))\
+      $(eval my_copy_dest := $(wordlist 2,999,$(my_copy_dest)))\
+      $(eval my_copy_dest := $(subst $(space),/,$(my_copy_dest)))\
+      $(eval my_copy_pairs += $(bui):$(my_staging_dir)/$(my_copy_dest)))\
+  ))
+
+# Collect CUSTOM_IMAGE_COPY_FILES.
+my_image_copy_files :=
+$(foreach f,$(CUSTOM_IMAGE_COPY_FILES),\
+  $(eval pair := $(subst :,$(space),$(f)))\
+  $(eval src := $(word 1,$(pair)))\
+  $(eval my_image_copy_files += $(src))\
+  $(eval my_copy_pairs += $(src):$(my_staging_dir)/$(word 2,$(pair))))
+
+$(my_built_custom_image): PRIVATE_INTERMEDIATES := $(intermediates)
+$(my_built_custom_image): PRIVATE_MOUNT_POINT := $(CUSTOM_IMAGE_MOUNT_POINT)
+$(my_built_custom_image): PRIVATE_PARTITION_SIZE := $(CUSTOM_IMAGE_PARTITION_SIZE)
+$(my_built_custom_image): PRIVATE_FILE_SYSTEM_TYPE := $(CUSTOM_IMAGE_FILE_SYSTEM_TYPE)
+$(my_built_custom_image): PRIVATE_STAGING_DIR := $(my_staging_dir)
+$(my_built_custom_image): PRIVATE_COPY_PAIRS := $(my_copy_pairs)
+$(my_built_custom_image): PRIVATE_PICKUP_FILES := $(my_pickup_files)
+$(my_built_custom_image): PRIVATE_DICT_FILE := $(CUSTOM_IMAGE_DICT_FILE)
+$(my_built_custom_image): $(INTERNAL_USERIMAGES_DEPS) $(my_built_modules) $(my_image_copy_files) \
+  $(CUSTOM_IMAGE_DICT_FILE)
+	@echo "Build image $@"
+	$(hide) rm -rf $(PRIVATE_INTERMEDIATES) && mkdir -p $(PRIVATE_INTERMEDIATES)
+	$(hide) rm -rf $(PRIVATE_STAGING_DIR) && mkdir -p $(PRIVATE_STAGING_DIR)
+	# Copy all the files.
+	$(hide) $(foreach p,$(PRIVATE_COPY_PAIRS),\
+	          $(eval pair := $(subst :,$(space),$(p)))\
+	          mkdir -p $(dir $(word 2,$(pair)));\
+	          cp -Rf $(word 1,$(pair)) $(word 2,$(pair));)
+	$(if $($(PRIVATE_PICKUP_FILES)),$(hide) cp -Rf $(PRIVATE_PICKUP_FILES) $(PRIVATE_STAGING_DIR))
+	# Generate the dict.
+	$(hide) echo "# For all accepted properties, see BuildImage() in tools/releasetools/build_image.py" > $(PRIVATE_INTERMEDIATES)/image_info.txt
+	$(hide) echo "mount_point=$(PRIVATE_MOUNT_POINT)" >> $(PRIVATE_INTERMEDIATES)/image_info.txt
+	$(hide) echo "fs_type=$(PRIVATE_FILE_SYSTEM_TYPE)" >> $(PRIVATE_INTERMEDIATES)/image_info.txt
+	$(hide) echo "partition_size=$(PRIVATE_PARTITION_SIZE)" >> $(PRIVATE_INTERMEDIATES)/image_info.txt
+	$(if $(PRIVATE_DICT_FILE),\
+	  $(hide) echo "# Properties from $(PRIVATE_DICT_FILE)" >> $(PRIVATE_INTERMEDIATES)/image_info.txt;\
+	  cat $(PRIVATE_DICT_FILE) >> $(PRIVATE_INTERMEDIATES)/image_info.txt)
+	# Generate the image.
+	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH \
+	  ./build/tools/releasetools/build_image.py \
+	  $(PRIVATE_STAGING_DIR) $(PRIVATE_INTERMEDIATES)/image_info.txt $@
+
+my_installed_custom_image := $(PRODUCT_OUT)/$(notdir $(my_built_custom_image))
+$(my_installed_custom_image) : $(my_built_custom_image)
+	$(call copy-file-to-new-target-with-cp)
+
+.PHONY: $(my_custom_image_name)
+custom_images $(my_custom_image_name) : $(my_installed_custom_image)
+
+# Archive the built image.
+$(call dist-for-goals, $(my_custom_image_name) custom_images,$(my_installed_custom_image))
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index abfa072..d87a032 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -41,7 +41,7 @@
   # which is the version that we reveal to the end user.
   # Update this value when the platform version changes (rather
   # than overriding it somewhere else).  Can be an arbitrary string.
-  PLATFORM_VERSION := 5.0.2
+  PLATFORM_VERSION := 5.1
 endif
 
 ifeq "" "$(PLATFORM_SDK_VERSION)"
@@ -53,7 +53,7 @@
   # intermediate builds).  During development, this number remains at the
   # SDK version the branch is based on and PLATFORM_VERSION_CODENAME holds
   # the code-name of the new development work.
-  PLATFORM_SDK_VERSION := 21
+  PLATFORM_SDK_VERSION := 22
 endif
 
 ifeq "" "$(PLATFORM_VERSION_CODENAME)"
diff --git a/envsetup.sh b/envsetup.sh
index a9bd707..d80e95c 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -570,7 +570,8 @@
 {
     local arch="$(echo $* | xargs -n 1 echo | \grep -E '^(arm|x86|mips|armv5|arm64|x86_64|mips64)$' | xargs)"
     local variant="$(echo $* | xargs -n 1 echo | \grep -E '^(user|userdebug|eng)$' | xargs)"
-    local apps="$(echo $* | xargs -n 1 echo | \grep -E -v '^(user|userdebug|eng|arm|x86|mips|armv5|arm64|x86_64|mips64)$' | xargs)"
+    local density="$(echo $* | xargs -n 1 echo | \grep -E '^(ldpi|mdpi|tvdpi|hdpi|xhdpi|xxhdpi|xxxhdpi|alldpi)$' | xargs)"
+    local apps="$(echo $* | xargs -n 1 echo | \grep -E -v '^(user|userdebug|eng|arm|x86|mips|armv5|arm64|x86_64|mips64|ldpi|mdpi|tvdpi|hdpi|xhdpi|xxhdpi|xxxhdpi|alldpi)$' | xargs)"
 
     if [ $(echo $arch | wc -w) -gt 1 ]; then
         echo "tapas: Error: Multiple build archs supplied: $arch"
@@ -580,6 +581,10 @@
         echo "tapas: Error: Multiple build variants supplied: $variant"
         return
     fi
+    if [ $(echo $density | wc -w) -gt 1 ]; then
+        echo "tapas: Error: Multiple densities supplied: $density"
+        return
+    fi
 
     local product=full
     case $arch in
@@ -596,9 +601,13 @@
     if [ -z "$apps" ]; then
         apps=all
     fi
+    if [ -z "$density" ]; then
+        density=alldpi
+    fi
 
     export TARGET_PRODUCT=$product
     export TARGET_BUILD_VARIANT=$variant
+    export TARGET_BUILD_DENSITY=$density
     export TARGET_BUILD_TYPE=release
     export TARGET_BUILD_APPS=$apps
 
@@ -884,6 +893,85 @@
     fi
 }
 
+# coredump_setup - enable core dumps globally for any process
+#                  that has the core-file-size limit set correctly
+#
+# NOTE: You must call also coredump_enable for a specific process
+#       if its core-file-size limit is not set already.
+# NOTE: Core dumps are written to ramdisk; they will not survive a reboot!
+
+function coredump_setup()
+{
+	echo "Getting root...";
+	adb root;
+	adb wait-for-device;
+
+	echo "Remounting root parition read-write...";
+	adb shell mount -w -o remount -t rootfs rootfs;
+	sleep 1;
+	adb wait-for-device;
+	adb shell mkdir -p /cores;
+	adb shell mount -t tmpfs tmpfs /cores;
+	adb shell chmod 0777 /cores;
+
+	echo "Granting SELinux permission to dump in /cores...";
+	adb shell restorecon -R /cores;
+
+	echo "Set core pattern.";
+	adb shell 'echo /cores/core.%p > /proc/sys/kernel/core_pattern';
+
+	echo "Done."
+}
+
+# coredump_enable - enable core dumps for the specified process
+# $1 = PID of process (e.g., $(pid mediaserver))
+#
+# NOTE: coredump_setup must have been called as well for a core
+#       dump to actually be generated.
+
+function coredump_enable()
+{
+	local PID=$1;
+	if [ -z "$PID" ]; then
+		printf "Expecting a PID!\n";
+		return;
+	fi;
+	echo "Setting core limit for $PID to infinite...";
+	adb shell prlimit $PID 4 -1 -1
+}
+
+# core - send SIGV and pull the core for process
+# $1 = PID of process (e.g., $(pid mediaserver))
+#
+# NOTE: coredump_setup must be called once per boot for core dumps to be
+#       enabled globally.
+
+function core()
+{
+	local PID=$1;
+
+	if [ -z "$PID" ]; then
+		printf "Expecting a PID!\n";
+		return;
+	fi;
+
+	local CORENAME=core.$PID;
+	local COREPATH=/cores/$CORENAME;
+	local SIG=SEGV;
+
+	coredump_enable $1;
+
+	local done=0;
+	while [ $(adb shell "[ -d /proc/$PID ] && echo -n yes") ]; do
+		printf "\tSending SIG%s to %d...\n" $SIG $PID;
+		adb shell kill -$SIG $PID;
+		sleep 1;
+	done;
+
+	adb shell "while [ ! -f $COREPATH ] ; do echo waiting for $COREPATH to be generated; sleep 1; done"
+	echo "Done: core is under $COREPATH on device.";
+}
+
 # systemstack - dump the current stack trace of all threads in the system process
 # to the usual ANR traces file
 function systemstack()
@@ -967,10 +1055,151 @@
     fi
 }
 
+function adb_get_product_device() {
+  echo `adb shell getprop ro.product.device | sed s/.$//`
+}
+
+# returns 0 when process is not traced
+function adb_get_traced_by() {
+  echo `adb shell cat /proc/$1/status | grep -e "^TracerPid:" | sed "s/^TracerPid:\t//" | sed s/.$//`
+}
+
+function gdbclient() {
+  # TODO:
+  # 1. Check for ANDROID_SERIAL/multiple devices
+  local PROCESS_NAME="n/a"
+  local PID=$1
+  local PORT=5039
+  if [ -z "$PID" ]; then
+    echo "Usage: gdbclient <pid|processname> [port number]"
+    return -1
+  fi
+  local DEVICE=$(adb_get_product_device)
+
+  if [ -z "$DEVICE" ]; then
+    echo "Error: Unable to get device name. Please check if device is connected and ANDROID_SERIAL is set."
+    return -2
+  fi
+
+  if [ -n "$2" ]; then
+    PORT=$2
+  fi
+
+  local ROOT=$(gettop)
+  if [ -z "$ROOT" ]; then
+    # This is for the situation with downloaded symbols (from the build server)
+    # we check if they are available.
+    ROOT=`realpath .`
+  fi
+
+  local OUT_ROOT="$ROOT/out/target/product/$DEVICE"
+  local SYMBOLS_DIR="$OUT_ROOT/symbols"
+
+  if [ ! -d $SYMBOLS_DIR ]; then
+    echo "Error: couldn't find symbols: $SYMBOLS_DIR does not exist or is not a directory."
+    return -3
+  fi
+
+  # let's figure out which executable we are about to debug
+
+  # check if user specified a name -> resolve to pid
+  if [[ ! "$PID" =~ ^[0-9]+$ ]] ; then
+    PROCESS_NAME=$PID
+    PID=$(pid --exact $PROCESS_NAME)
+    if [ -z "$PID" ]; then
+      echo "Error: couldn't resolve pid by process name: $PROCESS_NAME"
+      return -4
+    fi
+  fi
+
+  local EXE=`adb shell readlink /proc/$PID/exe | sed s/.$//`
+  # TODO: print error in case there is no such pid
+  local LOCAL_EXE_PATH=$SYMBOLS_DIR$EXE
+
+  if [ ! -f $LOCAL_EXE_PATH ]; then
+    echo "Error: unable to find symbols for executable $EXE: file $LOCAL_EXE_PATH does not exist"
+    return -5
+  fi
+
+  local USE64BIT=""
+
+  if [[ "$(file $LOCAL_EXE_PATH)" =~ 64-bit ]]; then
+    USE64BIT="64"
+  fi
+
+  local GDB=
+  local GDB64=
+  local CPU_ABI=`adb shell getprop ro.product.cpu.abilist | sed s/.$//`
+  # TODO: we assume these are available via $PATH
+  if [[ $CPU_ABI =~ (^|,)arm64 ]]; then
+    GDB=arm-linux-androideabi-gdb
+    GDB64=aarch64-linux-android-gdb
+  elif [[ $CPU_ABI =~ (^|,)arm ]]; then
+    GDB=arm-linux-androideabi-gdb
+  elif [[ $CPU_ABI =~ (^|,)x86_64 ]]; then
+    GDB=x86_64-linux-androideabi-gdb
+  elif [[ $CPU_ABI =~ (^|,)x86 ]]; then
+    GDB=x86_64-linux-androideabi-gdb
+  elif [[ $CPU_ABI =~ (^|,)mips64 ]]; then
+    GDB=mipsel-linux-android-gdb
+    GDB64=mips64el-linux-android-gdb
+  elif [[ $CPU_ABI =~ (^|,)mips ]]; then
+    GDB=mipsel-linux-android-gdb
+  else
+    echo "Error: unrecognized cpu.abilist: $CPU_ABI"
+    return -6
+  fi
+
+  # TODO: check if tracing process is gdbserver and not some random strace...
+  if [ $(adb_get_traced_by $PID) -eq 0 ]; then
+    # start gdbserver
+    echo "Starting gdbserver..."
+    # TODO: check if adb is already listening $PORT
+    # to avoid unnecessary calls
+    echo ". adb forward for port=$PORT..."
+    adb forward tcp:$PORT tcp:$PORT
+    echo ". starting gdbserver to attach to pid=$PID..."
+    adb shell gdbserver$USE64BIT :$PORT --attach $PID &
+    echo ". give it couple of seconds to start..."
+    sleep 2
+    echo ". done"
+  else
+    echo "It looks like gdbserver is already attached to $PID (process is traced), trying to connect to it using local port=$PORT"
+  fi
+
+  local OUT_SO_SYMBOLS=$SYMBOLS_DIR/system/lib$USE64BIT
+  local OUT_VENDOR_SO_SYMBOLS=$SYMBOLS_DIR/vendor/lib$USE64BIT
+  local ART_CMD=""
+
+  echo >|"$OUT_ROOT/gdbclient.cmds" "set solib-absolute-prefix $SYMBOLS_DIR"
+  echo >>"$OUT_ROOT/gdbclient.cmds" "set solib-search-path $OUT_SO_SYMBOLS:$OUT_SO_SYMBOLS/hw:$OUT_SO_SYMBOLS/ssl/engines:$OUT_SO_SYMBOLS/drm:$OUT_SO_SYMBOLS/egl:$OUT_SO_SYMBOLS/soundfx:$OUT_VENDOR_SO_SYMBOLS:$OUT_VENDOR_SO_SYMBOLS/hw:$OUT_VENDOR_SO_SYMBOLS/egl"
+  local DALVIK_GDB_SCRIPT=$ROOT/development/scripts/gdb/dalvik.gdb
+  if [ -f $DALVIK_GDB_SCRIPT ]; then
+    echo >>"$OUT_ROOT/gdbclient.cmds" "source $DALVIK_GDB_SCRIPT"
+    ART_CMD="art-on"
+  else
+    echo "Warning: couldn't find $DALVIK_GDB_SCRIPT - ART debugging options will not be available"
+  fi
+  echo >>"$OUT_ROOT/gdbclient.cmds" "target remote :$PORT"
+  if [[ $EXE =~ (^|/)(app_process|dalvikvm)(|32|64)$ ]]; then
+    echo >> "$OUT_ROOT/gdbclient.cmds" $ART_CMD
+  fi
+
+  echo >>"$OUT_ROOT/gdbclient.cmds" ""
+
+  local WHICH_GDB=$GDB
+
+  if [ -n "$USE64BIT" -a -n "$GDB64" ]; then
+    WHICH_GDB=$GDB64
+  fi
+
+  gdbwrapper $WHICH_GDB "$OUT_ROOT/gdbclient.cmds" "$LOCAL_EXE_PATH"
+}
+
 # gdbclient now determines whether the user wants to debug a 32-bit or 64-bit
 # executable, set up the approriate gdbserver, then invokes the proper host
 # gdb.
-function gdbclient()
+function gdbclient_old()
 {
    local OUT_ROOT=$(get_abs_build_var PRODUCT_OUT)
    local OUT_SYMBOLS=$(get_abs_build_var TARGET_OUT_UNSTRIPPED)
diff --git a/target/board/generic_arm64/BoardConfig.mk b/target/board/generic_arm64/BoardConfig.mk
index 818f857..8afd5a8 100644
--- a/target/board/generic_arm64/BoardConfig.mk
+++ b/target/board/generic_arm64/BoardConfig.mk
@@ -76,7 +76,7 @@
 USE_OPENGL_RENDERER := true
 
 TARGET_USERIMAGES_USE_EXT4 := true
-BOARD_SYSTEMIMAGE_PARTITION_SIZE := 845427200
+BOARD_SYSTEMIMAGE_PARTITION_SIZE := 943718400
 BOARD_USERDATAIMAGE_PARTITION_SIZE := 576716800
 BOARD_CACHEIMAGE_PARTITION_SIZE := 69206016
 BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE := ext4
diff --git a/target/board/generic_mips/BoardConfig.mk b/target/board/generic_mips/BoardConfig.mk
index a319ad7..7cef968 100644
--- a/target/board/generic_mips/BoardConfig.mk
+++ b/target/board/generic_mips/BoardConfig.mk
@@ -50,7 +50,7 @@
 USE_OPENGL_RENDERER := true
 
 TARGET_USERIMAGES_USE_EXT4 := true
-BOARD_SYSTEMIMAGE_PARTITION_SIZE := 786432000
+BOARD_SYSTEMIMAGE_PARTITION_SIZE := 838860800
 BOARD_USERDATAIMAGE_PARTITION_SIZE := 576716800
 BOARD_CACHEIMAGE_PARTITION_SIZE := 69206016
 BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE := ext4
diff --git a/target/product/base.mk b/target/product/base.mk
index 28877c5..0d052b5 100644
--- a/target/product/base.mk
+++ b/target/product/base.mk
@@ -115,6 +115,9 @@
     wm
 
 
+PRODUCT_COPY_FILES := $(call add-to-product-copy-files-if-exists,\
+    frameworks/base/preloaded-classes:system/etc/preloaded-classes)
+
 # Note: it is acceptable to not have a compiled-classes file. In that case, all boot classpath
 #       classes will be compiled.
 PRODUCT_COPY_FILES += $(call add-to-product-copy-files-if-exists,\
diff --git a/target/product/full_base.mk b/target/product/full_base.mk
index 9b1a826..caace76 100644
--- a/target/product/full_base.mk
+++ b/target/product/full_base.mk
@@ -48,7 +48,7 @@
 PRODUCT_LOCALES := en_US
 
 # Include drawables for all densities
-PRODUCT_AAPT_CONFIG := normal hdpi xhdpi xxhdpi
+PRODUCT_AAPT_CONFIG := normal
 
 # Get some sounds
 $(call inherit-product-if-exists, frameworks/base/data/sounds/AllAudio.mk)
diff --git a/target/product/generic_no_telephony.mk b/target/product/generic_no_telephony.mk
index 0713db1..7af62ce 100644
--- a/target/product/generic_no_telephony.mk
+++ b/target/product/generic_no_telephony.mk
@@ -63,6 +63,7 @@
 $(call inherit-product-if-exists, external/google-fonts/carrois-gothic-sc/fonts.mk)
 $(call inherit-product-if-exists, external/google-fonts/coming-soon/fonts.mk)
 $(call inherit-product-if-exists, external/google-fonts/cutive-mono/fonts.mk)
+$(call inherit-product-if-exists, external/lohit-fonts/fonts.mk)
 $(call inherit-product-if-exists, external/noto-fonts/fonts.mk)
 $(call inherit-product-if-exists, external/naver-fonts/fonts.mk)
 $(call inherit-product-if-exists, frameworks/base/data/keyboards/keyboards.mk)
diff --git a/target/product/languages_full.mk b/target/product/languages_full.mk
index 030777e..6d77cde 100644
--- a/target/product/languages_full.mk
+++ b/target/product/languages_full.mk
@@ -21,4 +21,4 @@
 
 # These are all the locales that have translations and are displayable
 # by TextView in this branch.
-PRODUCT_LOCALES := en_AU en_US en_IN fr_FR it_IT es_ES et_EE de_DE nl_NL cs_CZ pl_PL ja_JP zh_TW zh_CN zh_HK ru_RU ko_KR nb_NO es_US da_DK el_GR tr_TR pt_PT pt_BR rm_CH sv_SE bg_BG ca_ES en_GB fi_FI hi_IN hr_HR hu_HU in_ID iw_IL lt_LT lv_LV ro_RO sk_SK sl_SI sr_RS uk_UA vi_VN tl_PH ar_EG fa_IR th_TH sw_TZ ms_MY af_ZA zu_ZA am_ET hi_IN en_XA ar_XB fr_CA km_KH lo_LA ne_NP si_LK mn_MN hy_AM az_AZ ka_GE my_MM mr_IN ml_IN is_IS mk_MK ky_KG eu_ES gl_ES bn_BD ta_IN kn_IN te_IN uz_UZ ur_PK kk_KZ
+PRODUCT_LOCALES := en_US en_AU en_IN fr_FR it_IT es_ES et_EE de_DE nl_NL cs_CZ pl_PL ja_JP zh_TW zh_CN zh_HK ru_RU ko_KR nb_NO es_US da_DK el_GR tr_TR pt_PT pt_BR rm_CH sv_SE bg_BG ca_ES en_GB fi_FI hi_IN hr_HR hu_HU in_ID iw_IL lt_LT lv_LV ro_RO sk_SK sl_SI sr_RS uk_UA vi_VN tl_PH ar_EG fa_IR th_TH sw_TZ ms_MY af_ZA zu_ZA am_ET hi_IN en_XA ar_XB fr_CA km_KH lo_LA ne_NP si_LK mn_MN hy_AM az_AZ ka_GE my_MM mr_IN ml_IN is_IS mk_MK ky_KG eu_ES gl_ES bn_BD ta_IN kn_IN te_IN uz_UZ ur_PK kk_KZ
diff --git a/target/product/sdk_base.mk b/target/product/sdk_base.mk
index 8610169..451c0b7 100644
--- a/target/product/sdk_base.mk
+++ b/target/product/sdk_base.mk
@@ -95,14 +95,10 @@
 -include external/svox/pico/lang/PicoLangFrFrInSystem.mk
 -include external/svox/pico/lang/PicoLangItItInSystem.mk
 
-# locale + densities. en_US is both first and in alphabetical order to
+# locale. en_US is both first and in alphabetical order to
 # ensure this is the default locale.
 PRODUCT_LOCALES := \
 	en_US \
-	ldpi \
-	hdpi \
-	mdpi \
-	xhdpi \
 	ar_EG \
 	ar_IL \
 	bg_BG \
diff --git a/target/product/security/verity.pk8 b/target/product/security/verity.pk8
new file mode 100644
index 0000000..bebf216
--- /dev/null
+++ b/target/product/security/verity.pk8
Binary files differ
diff --git a/target/product/security/verity.x509.pem b/target/product/security/verity.x509.pem
new file mode 100644
index 0000000..86399c3
--- /dev/null
+++ b/target/product/security/verity.x509.pem
@@ -0,0 +1,24 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/target/product/security/verity_key b/target/product/security/verity_key
index 8db965f..31982d9 100644
--- a/target/product/security/verity_key
+++ b/target/product/security/verity_key
Binary files differ
diff --git a/target/product/security/verity_private_dev_key b/target/product/security/verity_private_dev_key
deleted file mode 100644
index 92528e9..0000000
--- a/target/product/security/verity_private_dev_key
+++ /dev/null
@@ -1,28 +0,0 @@
------BEGIN PRIVATE KEY-----
-MIIEvAIBADANBgkqhkiG9w0BAQEFAASCBKYwggSiAgEAAoIBAQDQxdVrH2RB1eg5
-17/gBmLzW1Ds10RG6ctNZMhxppMOLnEZViKGv1VNRhxqK/JKTv2UujgZ94SJcDub
-G+DwAwaGZKQqDYUa0VU2cng8TYPcnYGPdJ7Usckp6tdg64vns7e+VVf0dOyEovR+
-JyeYUz05OhUMYP9xJIhpA2XnXe5Ekb9iTFSYo9uBpoXDD4IY7aOqUxSbv9wMtyIp
-dl+oTm0+kqRRi4KoxGHV0CzDseEUuWG/Kp/7aVF9Sg45NcC6KYvrGysUKA+Bt09O
-feDn/HRpT9SfRElJa5DRms33UBUtnom15F4yd4vvFgubB0nkPOUuwfZhTFfgeuY4
-H2bHkjKbAgMBAAECggEAMpFYqkPGQvQO9cO+ZALoAM4Dgfp6PTrv1WUt7+lLAUpa
-dqqYXk8F2Fu9EjJm03ziix237QI5Bhk7Nsy/5SK2d+L0qILx1JcTrsZ3PRQBdnRo
-J1k2B4qwkQii9oTXNF4hiWaekUWo7E+ULOJLAuhWkf/xjTgJZ1xT9iuuiSYFSnIa
-9ABNH0vCaKEkW/4ri6fdtXmO26C/ltJlnozl86x07PIFh4uBas7/40E8ykFP00CS
-zdhMh+2DGyCb1Q0eJ1IfGILNatkLNEd2BHgQ7qNBkN9yShZfhvIPblr5gSUlZplX
-diV20ZGLAfByKWgZZWKkwl9KzaisL/J/4dr2UlSVEQKBgQDxAYTsgoTkkP0TKzr3
-i3ljT8OuVOj6TwZVBJYe2MIJ3veivS3gWB53FpsKthbib7y8ifIakn15mQkNCK5R
-7H7F5lvZCNnB6shY5Dz7nLJxKLALcAg+d12l3gTbFQeFDs0iQQJF7P8hs/GPF7kY
-Layb7EF0uzYjyHJCKtFdaZaeZwKBgQDdwvCb7NJVeGTcE97etL+8acu9y4GlqKEF
-o0Vkw8TjNKj/KuDkbkAk9hXxU1ZCmDU3y6r8CVHYl0Sqh08plEhkYB/j3sFy81zY
-3xu/rLFysBwjeJHHlPjRTYkdKr9pABmm8NIEShvu9u8i+mpOhjbX72HxZL+i4Fou
-gz58wEdBrQKBgG8CfyKdn+7UJe3tbLTXRquK8xxauhGJ0uXYPfmpZ/8596C7OOVs
-UWQTQoj1hKb6RtolRCIfNbKL3hJl3D2aDG7Fg6r9m6fpqCzhvIE9FShwUF6EVRfI
-zZb4JA5xqkwMnEpZ3V0uI/p3Mx3xFG3ho+8SLLhC/1YOHysBI/y+BQWjAoGAYiqQ
-PkXYWhOAeleleeqDUdF3al3y1zVNimRbLJ7owjcmdEYz5YrUhEgXMIvWjIY6UKes
-2gL6IynbMK3TIjHM1fojQ8jw04TdXfdtnizBJGbHHgCab8IHXwe2oZ2xu7ZapKbI
-ITP5J5BSDabSdk49attB/Qy/NEeiRCK+/5RSNsUCgYAg6vX9VqMEkhPHeoFfdLGD
-EQPPN6QLrQ4Zif0GKxH96znNSv0rXdNp9t0kyapdgzMuCwIEuOkCSiKgmfjTWnYO
-qh5HMUuD2VbfWwI9jVujQMRmqiaFF7VxxA1bP5j1hJlI6cn1Fjlpi+NsNZN4nm3Q
-92SEwX2vDgjrU0NAtFFL1Q==
------END PRIVATE KEY-----
diff --git a/target/product/verity.mk b/target/product/verity.mk
index 4a1ca5e..0361b64 100644
--- a/target/product/verity.mk
+++ b/target/product/verity.mk
@@ -17,7 +17,11 @@
 # Provides dependencies necessary for verified boot
 
 PRODUCT_SUPPORTS_VERITY := true
-PRODUCT_VERITY_SIGNING_KEY := build/target/product/security/verity_private_dev_key
+
+# The dev key is used to sign boot and recovery images, and the verity
+# metadata table. Actual product deliverables will be re-signed by hand.
+# We expect this file to exist with the suffixes ".x509.pem" and ".pk8".
+PRODUCT_VERITY_SIGNING_KEY := build/target/product/security/verity
 
 PRODUCT_PACKAGES += \
         verity_key
diff --git a/tools/buildinfo.sh b/tools/buildinfo.sh
index ed6bd87..a80b2db 100755
--- a/tools/buildinfo.sh
+++ b/tools/buildinfo.sh
@@ -16,6 +16,7 @@
 echo "ro.build.user=$USER"
 echo "ro.build.host=`hostname`"
 echo "ro.build.tags=$BUILD_VERSION_TAGS"
+echo "ro.build.flavor=$TARGET_BUILD_FLAVOR"
 echo "ro.product.model=$PRODUCT_MODEL"
 echo "ro.product.brand=$PRODUCT_BRAND"
 echo "ro.product.name=$PRODUCT_NAME"
diff --git a/tools/releasetools/blockimgdiff.py b/tools/releasetools/blockimgdiff.py
index 216486c..8b179d5 100644
--- a/tools/releasetools/blockimgdiff.py
+++ b/tools/releasetools/blockimgdiff.py
@@ -16,6 +16,7 @@
 
 from collections import deque, OrderedDict
 from hashlib import sha1
+import heapq
 import itertools
 import multiprocessing
 import os
@@ -142,9 +143,16 @@
     self.goes_before = {}
     self.goes_after = {}
 
+    self.stash_before = []
+    self.use_stash = []
+
     self.id = len(by_id)
     by_id.append(self)
 
+  def NetStashChange(self):
+    return (sum(sr.size() for (_, sr) in self.stash_before) -
+            sum(sr.size() for (_, sr) in self.use_stash))
+
   def __str__(self):
     return (str(self.id) + ": <" + str(self.src_ranges) + " " + self.style +
             " to " + str(self.tgt_ranges) + ">")
@@ -182,11 +190,14 @@
 # original image.
 
 class BlockImageDiff(object):
-  def __init__(self, tgt, src=None, threads=None):
+  def __init__(self, tgt, src=None, threads=None, version=2):
     if threads is None:
       threads = multiprocessing.cpu_count() // 2
       if threads == 0: threads = 1
     self.threads = threads
+    self.version = version
+
+    assert version in (1, 2)
 
     self.tgt = tgt
     if src is None:
@@ -221,7 +232,12 @@
     self.FindVertexSequence()
     # Fix up the ordering dependencies that the sequence didn't
     # satisfy.
-    self.RemoveBackwardEdges()
+    if self.version == 1:
+      self.RemoveBackwardEdges()
+    else:
+      self.ReverseBackwardEdges()
+      self.ImproveVertexSequence()
+
     # Double-check our work.
     self.AssertSequenceGood()
 
@@ -231,18 +247,87 @@
   def WriteTransfers(self, prefix):
     out = []
 
-    out.append("1\n")   # format version number
     total = 0
     performs_read = False
 
+    stashes = {}
+    stashed_blocks = 0
+    max_stashed_blocks = 0
+
+    free_stash_ids = []
+    next_stash_id = 0
+
     for xf in self.transfers:
 
-      # zero [rangeset]
-      # new [rangeset]
-      # bsdiff patchstart patchlen [src rangeset] [tgt rangeset]
-      # imgdiff patchstart patchlen [src rangeset] [tgt rangeset]
-      # move [src rangeset] [tgt rangeset]
-      # erase [rangeset]
+      if self.version < 2:
+        assert not xf.stash_before
+        assert not xf.use_stash
+
+      for s, sr in xf.stash_before:
+        assert s not in stashes
+        if free_stash_ids:
+          sid = heapq.heappop(free_stash_ids)
+        else:
+          sid = next_stash_id
+          next_stash_id += 1
+        stashes[s] = sid
+        stashed_blocks += sr.size()
+        out.append("stash %d %s\n" % (sid, sr.to_string_raw()))
+
+      if stashed_blocks > max_stashed_blocks:
+        max_stashed_blocks = stashed_blocks
+
+      if self.version == 1:
+        src_string = xf.src_ranges.to_string_raw()
+      elif self.version == 2:
+
+        #   <# blocks> <src ranges>
+        #     OR
+        #   <# blocks> <src ranges> <src locs> <stash refs...>
+        #     OR
+        #   <# blocks> - <stash refs...>
+
+        size = xf.src_ranges.size()
+        src_string = [str(size)]
+
+        unstashed_src_ranges = xf.src_ranges
+        mapped_stashes = []
+        for s, sr in xf.use_stash:
+          sid = stashes.pop(s)
+          stashed_blocks -= sr.size()
+          unstashed_src_ranges = unstashed_src_ranges.subtract(sr)
+          sr = xf.src_ranges.map_within(sr)
+          mapped_stashes.append(sr)
+          src_string.append("%d:%s" % (sid, sr.to_string_raw()))
+          heapq.heappush(free_stash_ids, sid)
+
+        if unstashed_src_ranges:
+          src_string.insert(1, unstashed_src_ranges.to_string_raw())
+          if xf.use_stash:
+            mapped_unstashed = xf.src_ranges.map_within(unstashed_src_ranges)
+            src_string.insert(2, mapped_unstashed.to_string_raw())
+            mapped_stashes.append(mapped_unstashed)
+            self.AssertPartition(RangeSet(data=(0, size)), mapped_stashes)
+        else:
+          src_string.insert(1, "-")
+          self.AssertPartition(RangeSet(data=(0, size)), mapped_stashes)
+
+        src_string = " ".join(src_string)
+
+      # both versions:
+      #   zero <rangeset>
+      #   new <rangeset>
+      #   erase <rangeset>
+      #
+      # version 1:
+      #   bsdiff patchstart patchlen <src rangeset> <tgt rangeset>
+      #   imgdiff patchstart patchlen <src rangeset> <tgt rangeset>
+      #   move <src rangeset> <tgt rangeset>
+      #
+      # version 2:
+      #   bsdiff patchstart patchlen <tgt rangeset> <src_string>
+      #   imgdiff patchstart patchlen <tgt rangeset> <src_string>
+      #   move <tgt rangeset> <src_string>
 
       tgt_size = xf.tgt_ranges.size()
 
@@ -255,17 +340,27 @@
         assert xf.tgt_ranges
         assert xf.src_ranges.size() == tgt_size
         if xf.src_ranges != xf.tgt_ranges:
-          out.append("%s %s %s\n" % (
-              xf.style,
-              xf.src_ranges.to_string_raw(), xf.tgt_ranges.to_string_raw()))
+          if self.version == 1:
+            out.append("%s %s %s\n" % (
+                xf.style,
+                xf.src_ranges.to_string_raw(), xf.tgt_ranges.to_string_raw()))
+          elif self.version == 2:
+            out.append("%s %s %s\n" % (
+                xf.style,
+                xf.tgt_ranges.to_string_raw(), src_string))
           total += tgt_size
       elif xf.style in ("bsdiff", "imgdiff"):
         performs_read = True
         assert xf.tgt_ranges
         assert xf.src_ranges
-        out.append("%s %d %d %s %s\n" % (
-            xf.style, xf.patch_start, xf.patch_len,
-            xf.src_ranges.to_string_raw(), xf.tgt_ranges.to_string_raw()))
+        if self.version == 1:
+          out.append("%s %d %d %s %s\n" % (
+              xf.style, xf.patch_start, xf.patch_len,
+              xf.src_ranges.to_string_raw(), xf.tgt_ranges.to_string_raw()))
+        elif self.version == 2:
+          out.append("%s %d %d %s %s\n" % (
+              xf.style, xf.patch_start, xf.patch_len,
+              xf.tgt_ranges.to_string_raw(), src_string))
         total += tgt_size
       elif xf.style == "zero":
         assert xf.tgt_ranges
@@ -276,7 +371,10 @@
       else:
         raise ValueError, "unknown transfer style '%s'\n" % (xf.style,)
 
-    out.insert(1, str(total) + "\n")
+
+      # sanity check: abort if we're going to need more than 512 MB if
+      # stash space
+      assert max_stashed_blocks * self.tgt.blocksize < (512 << 20)
 
     all_tgt = RangeSet(data=(0, self.tgt.total_blocks))
     if performs_read:
@@ -289,12 +387,24 @@
     else:
       # if nothing is read (ie, this is a full OTA), then we can start
       # by erasing the entire partition.
-      out.insert(2, "erase %s\n" % (all_tgt.to_string_raw(),))
+      out.insert(0, "erase %s\n" % (all_tgt.to_string_raw(),))
+
+    out.insert(0, "%d\n" % (self.version,))   # format version number
+    out.insert(1, str(total) + "\n")
+    if self.version >= 2:
+      # version 2 only: after the total block count, we give the number
+      # of stash slots needed, and the maximum size needed (in blocks)
+      out.insert(2, str(next_stash_id) + "\n")
+      out.insert(3, str(max_stashed_blocks) + "\n")
 
     with open(prefix + ".transfer.list", "wb") as f:
       for i in out:
         f.write(i)
 
+    if self.version >= 2:
+      print("max stashed blocks: %d  (%d bytes)\n" % (
+          max_stashed_blocks, max_stashed_blocks * self.tgt.blocksize))
+
   def ComputePatches(self, prefix):
     print("Reticulating splines...")
     diff_q = []
@@ -409,7 +519,13 @@
     # Imagine processing the transfers in order.
     for xf in self.transfers:
       # Check that the input blocks for this transfer haven't yet been touched.
-      assert not touched.overlaps(xf.src_ranges)
+
+      x = xf.src_ranges
+      if self.version >= 2:
+        for _, sr in xf.use_stash:
+          x = x.subtract(sr)
+
+      assert not touched.overlaps(x)
       # Check that the output blocks for this transfer haven't yet been touched.
       assert not touched.overlaps(xf.tgt_ranges)
       # Touch all the blocks written by this transfer.
@@ -418,6 +534,47 @@
     # Check that we've written every target block.
     assert touched == self.tgt.care_map
 
+  def ImproveVertexSequence(self):
+    print("Improving vertex order...")
+
+    # At this point our digraph is acyclic; we reversed any edges that
+    # were backwards in the heuristically-generated sequence.  The
+    # previously-generated order is still acceptable, but we hope to
+    # find a better order that needs less memory for stashed data.
+    # Now we do a topological sort to generate a new vertex order,
+    # using a greedy algorithm to choose which vertex goes next
+    # whenever we have a choice.
+
+    # Make a copy of the edge set; this copy will get destroyed by the
+    # algorithm.
+    for xf in self.transfers:
+      xf.incoming = xf.goes_after.copy()
+      xf.outgoing = xf.goes_before.copy()
+
+    L = []   # the new vertex order
+
+    # S is the set of sources in the remaining graph; we always choose
+    # the one that leaves the least amount of stashed data after it's
+    # executed.
+    S = [(u.NetStashChange(), u.order, u) for u in self.transfers
+         if not u.incoming]
+    heapq.heapify(S)
+
+    while S:
+      _, _, xf = heapq.heappop(S)
+      L.append(xf)
+      for u in xf.outgoing:
+        del u.incoming[xf]
+        if not u.incoming:
+          heapq.heappush(S, (u.NetStashChange(), u.order, u))
+
+    # if this fails then our graph had a cycle.
+    assert len(L) == len(self.transfers)
+
+    self.transfers = L
+    for i, xf in enumerate(L):
+      xf.order = i
+
   def RemoveBackwardEdges(self):
     print("Removing backward edges...")
     in_order = 0
@@ -425,19 +582,17 @@
     lost_source = 0
 
     for xf in self.transfers:
-      io = 0
-      ooo = 0
       lost = 0
       size = xf.src_ranges.size()
       for u in xf.goes_before:
         # xf should go before u
         if xf.order < u.order:
           # it does, hurray!
-          io += 1
+          in_order += 1
         else:
           # it doesn't, boo.  trim the blocks that u writes from xf's
           # source, so that xf can go after u.
-          ooo += 1
+          out_of_order += 1
           assert xf.src_ranges.overlaps(u.tgt_ranges)
           xf.src_ranges = xf.src_ranges.subtract(u.tgt_ranges)
           xf.intact = False
@@ -448,8 +603,6 @@
 
       lost = size - xf.src_ranges.size()
       lost_source += lost
-      in_order += io
-      out_of_order += ooo
 
     print(("  %d/%d dependencies (%.2f%%) were violated; "
            "%d source blocks removed.") %
@@ -458,6 +611,48 @@
            if (in_order + out_of_order) else 0.0,
            lost_source))
 
+  def ReverseBackwardEdges(self):
+    print("Reversing backward edges...")
+    in_order = 0
+    out_of_order = 0
+    stashes = 0
+    stash_size = 0
+
+    for xf in self.transfers:
+      lost = 0
+      size = xf.src_ranges.size()
+      for u in xf.goes_before.copy():
+        # xf should go before u
+        if xf.order < u.order:
+          # it does, hurray!
+          in_order += 1
+        else:
+          # it doesn't, boo.  modify u to stash the blocks that it
+          # writes that xf wants to read, and then require u to go
+          # before xf.
+          out_of_order += 1
+
+          overlap = xf.src_ranges.intersect(u.tgt_ranges)
+          assert overlap
+
+          u.stash_before.append((stashes, overlap))
+          xf.use_stash.append((stashes, overlap))
+          stashes += 1
+          stash_size += overlap.size()
+
+          # reverse the edge direction; now xf must go after u
+          del xf.goes_before[u]
+          del u.goes_after[xf]
+          xf.goes_after[u] = None    # value doesn't matter
+          u.goes_before[xf] = None
+
+    print(("  %d/%d dependencies (%.2f%%) were violated; "
+           "%d source blocks stashed.") %
+          (out_of_order, in_order + out_of_order,
+           (out_of_order * 100.0 / (in_order + out_of_order))
+           if (in_order + out_of_order) else 0.0,
+           stash_size))
+
   def FindVertexSequence(self):
     print("Finding vertex sequence...")
 
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 5d87864..24d5665 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -160,7 +160,7 @@
   # get properties
   image_size = prop_dict["partition_size"]
   block_dev = prop_dict["verity_block_device"]
-  signer_key = prop_dict["verity_key"]
+  signer_key = prop_dict["verity_key"] + ".pk8"
   signer_path = prop_dict["verity_signer_cmd"]
 
   # make a tempdir
@@ -368,23 +368,28 @@
   out_file = argv[2]
 
   glob_dict = LoadGlobalDict(glob_dict_file)
-  image_filename = os.path.basename(out_file)
-  mount_point = ""
-  if image_filename == "system.img":
-    mount_point = "system"
-  elif image_filename == "userdata.img":
-    mount_point = "data"
-  elif image_filename == "cache.img":
-    mount_point = "cache"
-  elif image_filename == "vendor.img":
-    mount_point = "vendor"
-  elif image_filename == "oem.img":
-    mount_point = "oem"
+  if "mount_point" in glob_dict:
+    # The caller knows the mount point and provides a dictionay needed by BuildImage().
+    image_properties = glob_dict
   else:
-    print >> sys.stderr, "error: unknown image file name ", image_filename
-    exit(1)
+    image_filename = os.path.basename(out_file)
+    mount_point = ""
+    if image_filename == "system.img":
+      mount_point = "system"
+    elif image_filename == "userdata.img":
+      mount_point = "data"
+    elif image_filename == "cache.img":
+      mount_point = "cache"
+    elif image_filename == "vendor.img":
+      mount_point = "vendor"
+    elif image_filename == "oem.img":
+      mount_point = "oem"
+    else:
+      print >> sys.stderr, "error: unknown image file name ", image_filename
+      exit(1)
 
-  image_properties = ImagePropFromGlobalDict(glob_dict, mount_point)
+    image_properties = ImagePropFromGlobalDict(glob_dict, mount_point)
+
   if not BuildImage(in_dir, image_properties, out_file):
     print >> sys.stderr, "error: failed to build %s from %s" % (out_file, in_dir)
     exit(1)
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 815c76c..a596c26 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -347,7 +347,7 @@
 
   if info_dict.get("verity_key", None):
     path = "/" + os.path.basename(sourcedir).lower()
-    cmd = ["boot_signer", path, img.name, info_dict["verity_key"], img.name]
+    cmd = ["boot_signer", path, img.name, info_dict["verity_key"] + ".pk8", info_dict["verity_key"] + ".x509.pem", img.name]
     p = Run(cmd, stdout=subprocess.PIPE)
     p.communicate()
     assert p.returncode == 0, "boot_signer of %s image failed" % path
@@ -1024,13 +1024,22 @@
 
 
 class BlockDifference:
-  def __init__(self, partition, tgt, src=None, check_first_block=False):
+  def __init__(self, partition, tgt, src=None, check_first_block=False, version=None):
     self.tgt = tgt
     self.src = src
     self.partition = partition
     self.check_first_block = check_first_block
 
-    b = blockimgdiff.BlockImageDiff(tgt, src, threads=OPTIONS.worker_threads)
+    if version is None:
+      version = 1
+      if OPTIONS.info_dict:
+        version = max(
+            int(i) for i in
+            OPTIONS.info_dict.get("blockimgdiff_versions", "1").split(","))
+    self.version = version
+
+    b = blockimgdiff.BlockImageDiff(tgt, src, threads=OPTIONS.worker_threads,
+                                    version=self.version)
     tmpdir = tempfile.mkdtemp()
     OPTIONS.tempfiles.append(tmpdir)
     self.path = os.path.join(tmpdir, partition)
@@ -1041,9 +1050,16 @@
   def WriteScript(self, script, output_zip, progress=None):
     if not self.src:
       # write the output unconditionally
-      if progress: script.ShowProgress(progress, 0)
-      self._WriteUpdate(script, output_zip)
+      script.Print("Patching %s image unconditionally..." % (self.partition,))
+    else:
+      script.Print("Patching %s image after verification." % (self.partition,))
 
+    if progress: script.ShowProgress(progress, 0)
+    self._WriteUpdate(script, output_zip)
+
+  def WriteVerifyScript(self, script):
+    if not self.src:
+      script.Print("Image %s will be patched unconditionally." % (self.partition,))
     else:
       if self.check_first_block:
         self._CheckFirstBlock(script)
@@ -1051,15 +1067,20 @@
       script.AppendExtra('if range_sha1("%s", "%s") == "%s" then' %
                          (self.device, self.src.care_map.to_string_raw(),
                           self.src.TotalSha1()))
-      script.Print("Patching %s image..." % (self.partition,))
-      if progress: script.ShowProgress(progress, 0)
-      self._WriteUpdate(script, output_zip)
-      script.AppendExtra(('else\n'
-                          '  (range_sha1("%s", "%s") == "%s") ||\n'
-                          '  abort("%s partition has unexpected contents");\n'
-                          'endif;') %
-                         (self.device, self.tgt.care_map.to_string_raw(),
-                          self.tgt.TotalSha1(), self.partition))
+      script.Print("Verified %s image..." % (self.partition,))
+      # Abort the OTA update if it doesn't support resumable OTA (i.e. version<3)
+      # and the checksum doesn't match the one in the source partition.
+      if self.version < 3:
+        script.AppendExtra(('else\n'
+                            '  abort("%s partition has unexpected contents");\n'
+                            'endif;') % (self.partition))
+      else:
+        script.AppendExtra(('else\n'
+                            '  (range_sha1("%s", "%s") == "%s") ||\n'
+                            '  abort("%s partition has unexpected contents");\n'
+                            'endif;') %
+                           (self.device, self.tgt.care_map.to_string_raw(),
+                            self.tgt.TotalSha1(), self.partition))
 
   def _WriteUpdate(self, script, output_zip):
     partition = self.partition
diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index 755e5c2..25309a4 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -558,6 +558,7 @@
 
   system_items = ItemSet("system", "META/filesystem_config.txt")
   script.ShowProgress(system_progress, 0)
+
   if block_based:
     # Full OTA is done as an "incremental" against an empty source
     # image.  This has the effect of writing new data from the package
@@ -739,8 +740,16 @@
 
   system_src = GetImage("system", OPTIONS.source_tmp, OPTIONS.source_info_dict)
   system_tgt = GetImage("system", OPTIONS.target_tmp, OPTIONS.target_info_dict)
+
+  blockimgdiff_version = 1
+  if OPTIONS.info_dict:
+    blockimgdiff_version = max(
+        int(i) for i in
+        OPTIONS.info_dict.get("blockimgdiff_versions", "1").split(","))
+
   system_diff = common.BlockDifference("system", system_tgt, system_src,
-                                       check_first_block=True)
+                                       check_first_block=True,
+                                       version=blockimgdiff_version)
 
   if HasVendorPartition(target_zip):
     if not HasVendorPartition(source_zip):
@@ -748,7 +757,8 @@
     vendor_src = GetImage("vendor", OPTIONS.source_tmp, OPTIONS.source_info_dict)
     vendor_tgt = GetImage("vendor", OPTIONS.target_tmp, OPTIONS.target_info_dict)
     vendor_diff = common.BlockDifference("vendor", vendor_tgt, vendor_src,
-                                         check_first_block=True)
+                                         check_first_block=True,
+                                         version=blockimgdiff_version)
   else:
     vendor_diff = None
 
@@ -809,11 +819,22 @@
   device_specific.IncrementalOTA_VerifyBegin()
 
   if oem_props is None:
-    script.AssertSomeFingerprint(source_fp, target_fp)
+    # When blockimgdiff version is less than 3 (non-resumable block-based OTA),
+    # patching on a device that's already on the target build will damage the
+    # system. Because operations like move don't check the block state, they
+    # always apply the changes unconditionally.
+    if blockimgdiff_version <= 2:
+      script.AssertSomeFingerprint(source_fp)
+    else:
+      script.AssertSomeFingerprint(source_fp, target_fp)
   else:
-    script.AssertSomeThumbprint(
-        GetBuildProp("ro.build.thumbprint", OPTIONS.target_info_dict),
-        GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))
+    if blockimgdiff_version <= 2:
+      script.AssertSomeThumbprint(
+          GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))
+    else:
+      script.AssertSomeThumbprint(
+          GetBuildProp("ro.build.thumbprint", OPTIONS.target_info_dict),
+          GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))
 
   if updating_boot:
     boot_type, boot_device = common.GetTypeAndDevice("/boot", OPTIONS.info_dict)
@@ -845,6 +866,11 @@
 else
 """ % bcb_dev)
 
+  # Verify the existing partitions.
+  system_diff.WriteVerifyScript(script)
+  if vendor_diff:
+    vendor_diff.WriteVerifyScript(script)
+
   script.Comment("---- start making changes here ----")
 
   device_specific.IncrementalOTA_InstallBegin()
diff --git a/tools/releasetools/rangelib.py b/tools/releasetools/rangelib.py
index 8a85d2d..7279c60 100644
--- a/tools/releasetools/rangelib.py
+++ b/tools/releasetools/rangelib.py
@@ -24,7 +24,9 @@
   lots of runs."""
 
   def __init__(self, data=None):
-    if data:
+    if isinstance(data, str):
+      self._parse_internal(data)
+    elif data:
       self.data = tuple(self._remove_pairs(data))
     else:
       self.data = ()
@@ -46,6 +48,9 @@
     else:
       return self.to_string()
 
+  def __repr__(self):
+    return '<RangeSet("' + self.to_string() + '")>'
+
   @classmethod
   def parse(cls, text):
     """Parse a text string consisting of a space-separated list of
@@ -59,7 +64,9 @@
     "15-20 30 10-14" is not, even though they represent the same set
     of blocks (and the two RangeSets will compare equal with ==).
     """
+    return cls(text)
 
+  def _parse_internal(self, text):
     data = []
     last = -1
     monotonic = True
@@ -81,9 +88,8 @@
         else:
           monotonic = True
     data.sort()
-    r = RangeSet(cls._remove_pairs(data))
-    r.monotonic = monotonic
-    return r
+    self.data = tuple(self._remove_pairs(data))
+    self.monotonic = monotonic
 
   @staticmethod
   def _remove_pairs(source):
@@ -113,7 +119,13 @@
 
   def union(self, other):
     """Return a new RangeSet representing the union of this RangeSet
-    with the argument."""
+    with the argument.
+
+    >>> RangeSet("10-19 30-34").union(RangeSet("18-29"))
+    <RangeSet("10-34")>
+    >>> RangeSet("10-19 30-34").union(RangeSet("22 32"))
+    <RangeSet("10-19 22 30-34")>
+    """
     out = []
     z = 0
     for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
@@ -125,7 +137,13 @@
 
   def intersect(self, other):
     """Return a new RangeSet representing the intersection of this
-    RangeSet with the argument."""
+    RangeSet with the argument.
+
+    >>> RangeSet("10-19 30-34").intersect(RangeSet("18-32"))
+    <RangeSet("18-19 30-32")>
+    >>> RangeSet("10-19 30-34").intersect(RangeSet("22-28"))
+    <RangeSet("")>
+    """
     out = []
     z = 0
     for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
@@ -137,7 +155,13 @@
 
   def subtract(self, other):
     """Return a new RangeSet representing subtracting the argument
-    from this RangeSet."""
+    from this RangeSet.
+
+    >>> RangeSet("10-19 30-34").subtract(RangeSet("18-32"))
+    <RangeSet("10-17 33-34")>
+    >>> RangeSet("10-19 30-34").subtract(RangeSet("22-28"))
+    <RangeSet("10-19 30-34")>
+    """
 
     out = []
     z = 0
@@ -150,7 +174,13 @@
 
   def overlaps(self, other):
     """Returns true if the argument has a nonempty overlap with this
-    RangeSet."""
+    RangeSet.
+
+    >>> RangeSet("10-19 30-34").overlaps(RangeSet("18-32"))
+    True
+    >>> RangeSet("10-19 30-34").overlaps(RangeSet("22-28"))
+    False
+    """
 
     # This is like intersect, but we can stop as soon as we discover the
     # output is going to be nonempty.
@@ -164,7 +194,11 @@
 
   def size(self):
     """Returns the total size of the RangeSet (ie, how many integers
-    are in the set)."""
+    are in the set).
+
+    >>> RangeSet("10-19 30-34").size()
+    15
+    """
 
     total = 0
     for i, p in enumerate(self.data):
@@ -173,3 +207,37 @@
       else:
         total -= p
     return total
+
+  def map_within(self, other):
+    """'other' should be a subset of 'self'.  Returns a RangeSet
+    representing what 'other' would get translated to if the integers
+    of 'self' were translated down to be contiguous starting at zero.
+
+    >>> RangeSet("0-9").map_within(RangeSet("3-4"))
+    <RangeSet("3-4")>
+    >>> RangeSet("10-19").map_within(RangeSet("13-14"))
+    <RangeSet("3-4")>
+    >>> RangeSet("10-19 30-39").map_within(RangeSet("17-19 30-32"))
+    <RangeSet("7-12")>
+    >>> RangeSet("10-19 30-39").map_within(RangeSet("12-13 17-19 30-32"))
+    <RangeSet("2-3 7-12")>
+    """
+
+    out = []
+    offset = 0
+    start = None
+    for p, d in heapq.merge(zip(self.data, itertools.cycle((-5, +5))),
+                            zip(other.data, itertools.cycle((-1, +1)))):
+      if d == -5:
+        start = p
+      elif d == +5:
+        offset += p-start
+        start = None
+      else:
+        out.append(offset + p - start)
+    return RangeSet(data=out)
+
+
+if __name__ == "__main__":
+  import doctest
+  doctest.testmod()
diff --git a/tools/releasetools/sign_target_files_apks b/tools/releasetools/sign_target_files_apks
index 075c925..931acb8 100755
--- a/tools/releasetools/sign_target_files_apks
+++ b/tools/releasetools/sign_target_files_apks
@@ -198,6 +198,7 @@
         print "NOT signing: %s" % (name,)
         output_tf_zip.writestr(out_info, data)
     elif info.filename in ("SYSTEM/build.prop",
+                           "VENDOR/build.prop",
                            "RECOVERY/RAMDISK/default.prop"):
       print "rewriting %s:" % (info.filename,)
       new_data = RewriteProps(data, misc_info)
@@ -295,12 +296,12 @@
     original_line = line
     if line and line[0] != '#' and "=" in line:
       key, value = line.split("=", 1)
-      if (key == "ro.build.fingerprint"
+      if (key in ("ro.build.fingerprint", "ro.vendor.build.fingerprint")
           and misc_info.get("oem_fingerprint_properties") is None):
         pieces = value.split("/")
         pieces[-1] = EditTags(pieces[-1])
         value = "/".join(pieces)
-      elif (key == "ro.build.thumbprint"
+      elif (key in ("ro.build.thumbprint", "ro.vendor.build.thumbprint")
           and misc_info.get("oem_fingerprint_properties") is not None):
         pieces = value.split("/")
         pieces[-1] = EditTags(pieces[-1])