diff --git a/CleanSpec.mk b/CleanSpec.mk
index 3e5d199..56a1cad 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -302,6 +302,11 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
 
+# 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/*)
+
 # Move to libc++ as the default STL.
 $(call add-clean-step, rm -rf $(OUT_DIR))
 
diff --git a/core/Makefile b/core/Makefile
index 43be804..c1f8826 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -491,6 +491,11 @@
 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 +510,14 @@
 $(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
@@ -674,6 +679,13 @@
 endif
 endif
 
+# These options tell the recovery updater/installer how to mount the partitions writebale.
+# <fstype>=<fstype_opts>[|<fstype_opts>]...
+# fstype_opts := <opt>[,<opt>]...
+#         opt := <name>[=<value>]
+# The following worked on Nexus devices with Kernel 3.1, 3.4, 3.10
+DEFAULT_TARGET_RECOVERY_FSTYPE_MOUNT_OPTIONS := ext4=max_batch_time=0,commit=1,data=ordered,barrier=1,errors=panic,nodelalloc
+
 ifneq (true,$(TARGET_USERIMAGES_SPARSE_EXT_DISABLED))
   INTERNAL_USERIMAGES_SPARSE_EXT_FLAG := -s
 endif
@@ -857,7 +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: $@ --------
@@ -1230,6 +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 \
@@ -1396,6 +1414,12 @@
 ifdef BOARD_RECOVERYIMAGE_PARTITION_SIZE
 	$(hide) echo "recovery_size=$(BOARD_RECOVERYIMAGE_PARTITION_SIZE)" >> $(zip_root)/META/misc_info.txt
 endif
+ifdef TARGET_RECOVERY_FSTYPE_MOUNT_OPTIONS
+	@# TARGET_RECOVERY_FSTYPE_MOUNT_OPTIONS can be empty to indicate that nothing but defaults should be used.
+	$(hide) echo "recovery_mount_options=$(TARGET_RECOVERY_FSTYPE_MOUNT_OPTIONS)" >> $(zip_root)/META/misc_info.txt
+else
+	$(hide) echo "recovery_mount_options=$(DEFAULT_TARGET_RECOVERY_FSTYPE_MOUNT_OPTIONS)" >> $(zip_root)/META/misc_info.txt
+endif
 	$(hide) echo "tool_extensions=$(tool_extensions)" >> $(zip_root)/META/misc_info.txt
 	$(hide) echo "default_system_dev_certificate=$(DEFAULT_SYSTEM_DEV_CERTIFICATE)" >> $(zip_root)/META/misc_info.txt
 ifdef PRODUCT_EXTRA_RECOVERY_KEYS
@@ -1405,6 +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
@@ -1497,10 +1522,14 @@
 name := $(name)-symbols-$(FILE_NAME_TAG)
 
 SYMBOLS_ZIP := $(PRODUCT_OUT)/$(name).zip
+# For apps_only build we'll establish the dependency later in build/core/main.mk.
+ifndef TARGET_BUILD_APPS
 $(SYMBOLS_ZIP): $(INSTALLED_SYSTEMIMAGE) $(INSTALLED_BOOTIMAGE_TARGET)
+endif
+$(SYMBOLS_ZIP):
 	@echo "Package symbols: $@"
 	$(hide) rm -rf $@
-	$(hide) mkdir -p $(dir $@)
+	$(hide) mkdir -p $(dir $@) $(TARGET_OUT_UNSTRIPPED)
 	$(hide) zip -qr $@ $(TARGET_OUT_UNSTRIPPED)
 
 # -----------------------------------------------------------------
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/binary.mk b/core/binary.mk
index 08e290a..75ec3cf 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -218,7 +218,9 @@
 
 ####################################################
 ## 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)
@@ -997,6 +999,21 @@
 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..c820ad5 100644
--- a/core/cleanbuild.mk
+++ b/core/cleanbuild.mk
@@ -220,6 +220,7 @@
 	$(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 8ee7734..f3f4ce9 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:=
@@ -166,6 +167,8 @@
 LOCAL_NO_FPIE :=
 LOCAL_CXX_STL := default
 LOCAL_NATIVE_COVERAGE :=
+LOCAL_DPI_VARIANTS:=
+LOCAL_DPI_FILE_STEM:=
 
 # arch specific variables
 LOCAL_SRC_FILES_$(TARGET_ARCH):=
diff --git a/core/combo/HOST_windows-x86.mk b/core/combo/HOST_windows-x86.mk
index d4acfe9..b71ac16 100644
--- a/core/combo/HOST_windows-x86.mk
+++ b/core/combo/HOST_windows-x86.mk
@@ -27,7 +27,7 @@
 ifdef USE_MINGW
 HOST_ACP_UNAVAILABLE := true
 TOOLS_EXE_SUFFIX :=
-$(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/java.mk b/core/java.mk
index 98d5138..bb634ac 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -64,6 +64,9 @@
 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/main.mk b/core/main.mk
index 7f4b217..53df32c 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -927,6 +927,9 @@
   $(PROGUARD_DICT_ZIP) : $(apps_only_installed_files)
   $(call dist-for-goals,apps_only, $(PROGUARD_DICT_ZIP))
 
+  $(SYMBOLS_ZIP) : $(apps_only_installed_files)
+  $(call dist-for-goals,apps_only, $(SYMBOLS_ZIP))
+
 .PHONY: apps_only
 apps_only: $(unbundled_build_modules)
 
diff --git a/core/package_internal.mk b/core/package_internal.mk
index bb458d4..e2c3cf4 100644
--- a/core/package_internal.mk
+++ b/core/package_internal.mk
@@ -192,6 +192,8 @@
 
 rs_compatibility_jni_libs :=
 
+include $(BUILD_SYSTEM)/android_manifest.mk
+
 #################################
 include $(BUILD_SYSTEM)/java.mk
 #################################
@@ -201,8 +203,6 @@
   LOCAL_SDK_RES_VERSION:=$(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, $(LOCAL_SDK_VERSION)))
diff --git a/core/prebuilt_internal.mk b/core/prebuilt_internal.mk
index 2e0d2ef..c19b278 100644
--- a/core/prebuilt_internal.mk
+++ b/core/prebuilt_internal.mk
@@ -117,6 +117,19 @@
 ifeq ($(LOCAL_MODULE_CLASS),APPS)
 PACKAGES.$(LOCAL_MODULE).OVERRIDES := $(strip $(LOCAL_OVERRIDES_PACKAGES))
 
+# Select dpi-specific source
+ifdef LOCAL_DPI_VARIANTS
+my_dpi := $(filter $(LOCAL_DPI_VARIANTS),$(PRODUCT_AAPT_PREF_CONFIG))
+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
 
@@ -250,10 +263,26 @@
 # 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/version_defaults.mk b/core/version_defaults.mk
index d2bef14..1acc320 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 := 5.0.50.50.50.50
+  PLATFORM_VERSION := LollipopMR1
 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 "" "$(PLATFORM_VERSION_CODENAME)"
diff --git a/envsetup.sh b/envsetup.sh
index 66f9136..ebf2cdc 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -570,7 +570,8 @@
 {
     local arch="$(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()
diff --git a/target/board/generic_arm64/BoardConfig.mk b/target/board/generic_arm64/BoardConfig.mk
index c57447d..818f857 100644
--- a/target/board/generic_arm64/BoardConfig.mk
+++ b/target/board/generic_arm64/BoardConfig.mk
@@ -25,13 +25,13 @@
 TARGET_2ND_CPU_ABI := armeabi-v7a
 TARGET_2ND_CPU_ABI2 := armeabi
 
-ifdef TARGET_BUILD_APPS
+ifneq ($(TARGET_BUILD_APPS)$(filter cts,$(MAKECMDGOALS)),)
 # DO NOT USE
 # DO NOT USE
 #
 # This architecture / CPU variant must NOT be used for any 64 bit
 # platform builds. It is the lowest common denominator required
-# to build an unbundled application for all supported 32 and 64 bit
+# to build an unbundled application or cts for all supported 32 and 64 bit
 # platforms.
 #
 # If you're building a 64 bit platform (and not an application) the
@@ -82,4 +82,3 @@
 BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE := ext4
 BOARD_FLASH_BLOCK_SIZE := 512
 TARGET_USERIMAGES_SPARSE_EXT_DISABLED := true
-
diff --git a/target/product/core.mk b/target/product/core.mk
index 876a536..519dbb8 100644
--- a/target/product/core.mk
+++ b/target/product/core.mk
@@ -15,9 +15,10 @@
 #
 
 # Base configuration for communication-oriented android devices
-# (phones, tablets, etc.).  If you want a change to apply to ALL
+# (phones, tablets, etc.).  If you want a change to apply to ALMOST ALL
 # devices (including non-phones and non-tablets), modify
-# core_minimal.mk instead.
+# core_minimal.mk instead. If you care about wearables, you need to modify
+# core_tiny.mk in addition to core_minimal.mk.
 
 PRODUCT_PACKAGES += \
     BasicDreams \
diff --git a/target/product/core_tiny.mk b/target/product/core_tiny.mk
index d6dbe98..9637e34 100644
--- a/target/product/core_tiny.mk
+++ b/target/product/core_tiny.mk
@@ -43,6 +43,7 @@
     DefaultContainerService \
     SettingsProvider \
     Shell \
+    bcc \
     bu \
     com.android.location.provider \
     com.android.location.provider.xml \
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/droiddoc/templates-sdk/assets/js/docs.js b/tools/droiddoc/templates-sdk/assets/js/docs.js
index a556f4f..08a0222 100644
--- a/tools/droiddoc/templates-sdk/assets/js/docs.js
+++ b/tools/droiddoc/templates-sdk/assets/js/docs.js
@@ -658,7 +658,7 @@
     setTimeout(updateSidenavFixedWidth,delay); // need to wait a moment for css to switch
     enabled = false;
   }
-  writeCookie("fullscreen", enabled, null, null);
+  writeCookie("fullscreen", enabled, null);
   setNavBarLeftPos();
   resizeNav(delay);
   updateSideNavPosition();
@@ -819,7 +819,7 @@
 function saveNavPanels() {
   var basePath = getBaseUri(location.pathname);
   var section = basePath.substring(1,basePath.indexOf("/",1));
-  writeCookie("height", resizePackagesNav.css("height"), section, null);
+  writeCookie("height", resizePackagesNav.css("height"), section);
 }
 
 
@@ -900,16 +900,12 @@
   return 0;
 }
 
-function writeCookie(cookie, val, section, expiration) {
+function writeCookie(cookie, val, section) {
   if (val==undefined) return;
   section = section == null ? "_" : "_"+section+"_";
-  if (expiration == null) {
-    var date = new Date();
-    date.setTime(date.getTime()+(10*365*24*60*60*1000)); // default expiration is one week
-    expiration = date.toGMTString();
-  }
+  var age = 2*365*24*60*60; // set max-age to 2 years
   var cookieValue = cookie_namespace + section + cookie + "=" + val
-                    + "; expires=" + expiration+"; path=/";
+                    + "; max-age=" + age +"; path=/";
   document.cookie = cookieValue;
 }
 
@@ -1149,9 +1145,7 @@
     nav_pref = NAV_PREF_TREE;
     init_default_navtree(toRoot);
   }
-  var date = new Date();
-  date.setTime(date.getTime()+(10*365*24*60*60*1000)); // keep this for 10 years
-  writeCookie("nav", nav_pref, "reference", date.toGMTString());
+  writeCookie("nav", nav_pref, "reference");
 
   $("#nav-panels").toggle();
   $("#panel-link").toggle();
@@ -1219,11 +1213,7 @@
 }
 
 function changeLangPref(lang, submit) {
-  var date = new Date();
-  expires = date.toGMTString(date.setTime(date.getTime()+(10*365*24*60*60*1000)));
-  // keep this for 50 years
-  //alert("expires: " + expires)
-  writeCookie("pref_lang", lang, null, expires);
+  writeCookie("pref_lang", lang, null);
 
   //  #######  TODO:  Remove this condition once we're stable on devsite #######
   //  This condition is only needed if we still need to support legacy GAE server
@@ -1988,7 +1978,7 @@
 
 
         // Search for matching JD docs
-        if (text.length >= 3) {
+        if (text.length >= 2) {
           // Regex to match only the beginning of a word
           var textRegex = new RegExp("\\b" + text.toLowerCase(), "g");
 
@@ -2732,10 +2722,7 @@
   selectedLevel = parseInt($("#apiLevelSelector option:selected").val());
   toggleVisisbleApis(selectedLevel, "body");
 
-  var date = new Date();
-  date.setTime(date.getTime()+(10*365*24*60*60*1000)); // keep this for 10 years
-  var expiration = date.toGMTString();
-  writeCookie(API_LEVEL_COOKIE, selectedLevel, null, expiration);
+  writeCookie(API_LEVEL_COOKIE, selectedLevel, null);
 
   if (selectedLevel < minLevel) {
     var thing = ($("#jd-header").html().indexOf("package") != -1) ? "package" : "class";
diff --git a/tools/droiddoc/templates-sdk/components/masthead.cs b/tools/droiddoc/templates-sdk/components/masthead.cs
index 2dde104..a04c523 100644
--- a/tools/droiddoc/templates-sdk/components/masthead.cs
+++ b/tools/droiddoc/templates-sdk/components/masthead.cs
@@ -160,6 +160,7 @@
         <div class="wrap" style="position:relative;z-index:1">
 
         <?cs if:reference ?>
+        <?cs # HIDE HELPOUTS RECRUIT BANNER
             <a id="helpoutsLink" class="resource resource-card resource-card-6x2x3 resource-card-6x2 helpouts-card" 
               href="http://helpouts.google.com/partner/landing/provider/googledevelopers" target="_blank">
               <div class="card-bg helpouts-card-bg"></div>
@@ -185,6 +186,7 @@
                 $("span#helpoutsLinkText").text(textB);
               }
             </script>
+        END HIDE HELPOUTS ?>
         <?cs /if ?>
 
             <ul class="nav-x col-9 develop" style="width:100%">
diff --git a/tools/droiddoc/templates-sdk/docpage.cs b/tools/droiddoc/templates-sdk/docpage.cs
index 7cd9d43..6199b23 100644
--- a/tools/droiddoc/templates-sdk/docpage.cs
+++ b/tools/droiddoc/templates-sdk/docpage.cs
@@ -194,10 +194,10 @@
 
 <?cs include:"trailer.cs" ?>
   <script src="https://developer.android.com/ytblogger_lists_unified.js" type="text/javascript"></script>
-  <script src="<?cs var:toroot ?>jd_lists_unified.js?v=3" type="text/javascript"></script>
-  <script src="<?cs var:toroot ?>jd_extras.js?v=4" type="text/javascript"></script>
-  <script src="<?cs var:toroot ?>jd_collections.js?v=4" type="text/javascript"></script>
-  <script src="<?cs var:toroot ?>jd_tag_helpers.js?v=3" type="text/javascript"></script>
+  <script src="<?cs var:toroot ?>jd_lists_unified.js?v=6" type="text/javascript"></script>
+  <script src="<?cs var:toroot ?>jd_extras.js?v=7" type="text/javascript"></script>
+  <script src="<?cs var:toroot ?>jd_collections.js?v=7" type="text/javascript"></script>
+  <script src="<?cs var:toroot ?>jd_tag_helpers.js?v=5" type="text/javascript"></script>
 
 </body>
 </html>
diff --git a/tools/droiddoc/templates-sdk/head_tag.cs b/tools/droiddoc/templates-sdk/head_tag.cs
index 7ecb7f9..d54f6e3 100644
--- a/tools/droiddoc/templates-sdk/head_tag.cs
+++ b/tools/droiddoc/templates-sdk/head_tag.cs
@@ -24,8 +24,8 @@
 <meta name="Description" content="<?cs var:page.metaDescription ?>"><?cs
   /if ?>
 <link rel="shortcut icon" type="image/x-icon" href="<?cs var:toroot ?>favicon.ico" />
-<title><?cs 
-  if:page.title ?><?cs 
+<title><?cs
+  if:page.title ?><?cs
     var:page.title ?> | <?cs
   /if ?>Android Developers</title>
 
@@ -64,6 +64,13 @@
 </script>
 <script src="<?cs var:toroot ?>assets/js/docs.js?v=2" type="text/javascript"></script>
 
+<?cs if:helpoutsWidget ?>
+<script type="text/javascript" src="https://helpouts.google.com/ps/res/embed.js" defer async
+    data-helpouts-embed data-helpouts-vertical="programming"
+    data-helpouts-tags="<?cs var:page.tags ?>" data-helpouts-prefix="android"
+    data-helpouts-standalone="true"></script>
+<?cs /if ?>
+
 <script>
   (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
   (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
diff --git a/tools/releasetools/add_img_to_target_files.py b/tools/releasetools/add_img_to_target_files.py
index bf217e0..e98e4b6 100755
--- a/tools/releasetools/add_img_to_target_files.py
+++ b/tools/releasetools/add_img_to_target_files.py
@@ -45,10 +45,28 @@
 
 OPTIONS = common.OPTIONS
 
+OPTIONS.add_missing = False
+OPTIONS.rebuild_recovery = False
 
-def AddSystem(output_zip, prefix="IMAGES/"):
+def AddSystem(output_zip, prefix="IMAGES/", recovery_img=None, boot_img=None):
   """Turn the contents of SYSTEM into a system image and store it in
   output_zip."""
+
+  prebuilt_path = os.path.join(OPTIONS.input_tmp, prefix, "system.img")
+  if os.path.exists(prebuilt_path):
+    print "system.img already exists in %s, no need to rebuild..." % (prefix,)
+    return
+
+  def output_sink(fn, data):
+     ofile = open(os.path.join(OPTIONS.input_tmp,"SYSTEM",fn), "w")
+     ofile.write(data)
+     ofile.close()
+
+  if OPTIONS.rebuild_recovery:
+    print("Building new recovery patch")
+    common.MakeRecoveryPatch(OPTIONS.input_tmp, output_sink, recovery_img, boot_img,
+                             info_dict=OPTIONS.info_dict)
+
   block_list = common.MakeTempFile(prefix="system-blocklist-", suffix=".map")
   imgname = BuildSystem(OPTIONS.input_tmp, OPTIONS.info_dict,
                         block_list=block_list)
@@ -67,6 +85,12 @@
 def AddVendor(output_zip, prefix="IMAGES/"):
   """Turn the contents of VENDOR into a vendor image and store in it
   output_zip."""
+
+  prebuilt_path = os.path.join(OPTIONS.input_tmp, prefix, "vendor.img")
+  if os.path.exists(prebuilt_path):
+    print "vendor.img already exists in %s, no need to rebuild..." % (prefix,)
+    return
+
   block_list = common.MakeTempFile(prefix="vendor-blocklist-", suffix=".map")
   imgname = BuildVendor(OPTIONS.input_tmp, OPTIONS.info_dict,
                      block_list=block_list)
@@ -131,6 +155,11 @@
 def AddUserdata(output_zip, prefix="IMAGES/"):
   """Create an empty userdata image and store it in output_zip."""
 
+  prebuilt_path = os.path.join(OPTIONS.input_tmp, prefix, "userdata.img")
+  if os.path.exists(prebuilt_path):
+    print "userdata.img already exists in %s, no need to rebuild..." % (prefix,)
+    return
+
   image_props = build_image.ImagePropFromGlobalDict(OPTIONS.info_dict,
                                                     "data")
   # We only allow yaffs to have a 0/missing partition_size.
@@ -165,6 +194,11 @@
 def AddCache(output_zip, prefix="IMAGES/"):
   """Create an empty cache image and store it in output_zip."""
 
+  prebuilt_path = os.path.join(OPTIONS.input_tmp, prefix, "cache.img")
+  if os.path.exists(prebuilt_path):
+    print "cache.img already exists in %s, no need to rebuild..." % (prefix,)
+    return
+
   image_props = build_image.ImagePropFromGlobalDict(OPTIONS.info_dict,
                                                     "cache")
   # The build system has to explicitly request for cache.img.
@@ -197,10 +231,11 @@
 def AddImagesToTargetFiles(filename):
   OPTIONS.input_tmp, input_zip = common.UnzipTemp(filename)
 
-  for n in input_zip.namelist():
-    if n.startswith("IMAGES/"):
-      print "target_files appears to already contain images."
-      sys.exit(1)
+  if not OPTIONS.add_missing:
+    for n in input_zip.namelist():
+      if n.startswith("IMAGES/"):
+        print "target_files appears to already contain images."
+        sys.exit(1)
 
   try:
     input_zip.getinfo("VENDOR/")
@@ -221,19 +256,35 @@
     print "\n\n++++ " + s + " ++++\n\n"
 
   banner("boot")
-  boot_image = common.GetBootableImage(
-      "IMAGES/boot.img", "boot.img", OPTIONS.input_tmp, "BOOT")
-  if boot_image:
-    boot_image.AddToZip(output_zip)
+  prebuilt_path = os.path.join(OPTIONS.input_tmp, "IMAGES", "boot.img")
+  boot_image = None
+  if os.path.exists(prebuilt_path):
+    print "boot.img already exists in IMAGES/, no need to rebuild..."
+    if OPTIONS.rebuild_recovery:
+      boot_image = common.GetBootableImage(
+          "IMAGES/boot.img", "boot.img", OPTIONS.input_tmp, "BOOT")
+  else:
+    boot_image = common.GetBootableImage(
+        "IMAGES/boot.img", "boot.img", OPTIONS.input_tmp, "BOOT")
+    if boot_image:
+      boot_image.AddToZip(output_zip)
 
   banner("recovery")
-  recovery_image = common.GetBootableImage(
-      "IMAGES/recovery.img", "recovery.img", OPTIONS.input_tmp, "RECOVERY")
-  if recovery_image:
-    recovery_image.AddToZip(output_zip)
+  recovery_image = None
+  prebuilt_path = os.path.join(OPTIONS.input_tmp, "IMAGES", "recovery.img")
+  if os.path.exists(prebuilt_path):
+    print "recovery.img already exists in IMAGES/, no need to rebuild..."
+    if OPTIONS.rebuild_recovery:
+      recovery_image = common.GetBootableImage(
+          "IMAGES/recovery.img", "recovery.img", OPTIONS.input_tmp, "RECOVERY")
+  else:
+    recovery_image = common.GetBootableImage(
+        "IMAGES/recovery.img", "recovery.img", OPTIONS.input_tmp, "RECOVERY")
+    if recovery_image:
+      recovery_image.AddToZip(output_zip)
 
   banner("system")
-  AddSystem(output_zip)
+  AddSystem(output_zip, recovery_img=recovery_image, boot_img=boot_image)
   if has_vendor:
     banner("vendor")
     AddVendor(output_zip)
@@ -244,9 +295,24 @@
 
   output_zip.close()
 
-
 def main(argv):
-  args = common.ParseOptions(argv, __doc__)
+
+  def option_handler(o, a):
+    if o in ("-a", "--add_missing"):
+      OPTIONS.add_missing = True
+    elif o in ("-r", "--rebuild_recovery",):
+      OPTIONS.rebuild_recovery = True
+    else:
+      return False
+    return True
+
+  args = common.ParseOptions(argv, __doc__,
+                             extra_opts="ar",
+                             extra_long_opts=["add_missing",
+                                              "rebuild_recovery",
+                                              ],
+                             extra_option_handler=option_handler)
+
 
   if len(args) != 1:
     common.Usage(__doc__)
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 a010e84..93b31e8 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
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 815c76c..6865a5d 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
@@ -1030,7 +1030,14 @@
     self.partition = partition
     self.check_first_block = check_first_block
 
-    b = blockimgdiff.BlockImageDiff(tgt, src, threads=OPTIONS.worker_threads)
+    version = 1
+    if OPTIONS.info_dict:
+      version = max(
+          int(i) for i in
+          OPTIONS.info_dict.get("blockimgdiff_versions", "1").split(","))
+
+    b = blockimgdiff.BlockImageDiff(tgt, src, threads=OPTIONS.worker_threads,
+                                    version=version)
     tmpdir = tempfile.mkdtemp()
     OPTIONS.tempfiles.append(tmpdir)
     self.path = os.path.join(tmpdir, partition)
diff --git a/tools/releasetools/edify_generator.py b/tools/releasetools/edify_generator.py
index 2bd071d..7d318a3 100644
--- a/tools/releasetools/edify_generator.py
+++ b/tools/releasetools/edify_generator.py
@@ -164,14 +164,25 @@
     self.script.append(('apply_patch_space(%d) || abort("Not enough free space '
                         'on /system to apply patches.");') % (amount,))
 
-  def Mount(self, mount_point):
-    """Mount the partition with the given mount_point."""
+  def Mount(self, mount_point, mount_options_by_format=""):
+    """Mount the partition with the given mount_point.
+      mount_options_by_format:
+      [fs_type=option[,option]...[|fs_type=option[,option]...]...]
+      where option is optname[=optvalue]
+      E.g. ext4=barrier=1,nodelalloc,errors=panic|f2fs=errors=recover
+    """
     fstab = self.info.get("fstab", None)
     if fstab:
       p = fstab[mount_point]
-      self.script.append('mount("%s", "%s", "%s", "%s");' %
+      mount_dict = {}
+      if mount_options_by_format is not None:
+        for option in mount_options_by_format.split("|"):
+          if "=" in option:
+            key, value = option.split("=", 1)
+            mount_dict[key] = value
+      self.script.append('mount("%s", "%s", "%s", "%s", "%s");' %
                          (p.fs_type, common.PARTITION_TYPES[p.fs_type],
-                          p.device, p.mount_point))
+                          p.device, p.mount_point, mount_dict.get(p.fs_type, "")))
       self.mounts.add(p.mount_point)
 
   def UnpackPackageDir(self, src, dst):
@@ -312,6 +323,10 @@
     """Append text verbatim to the output script."""
     self.script.append(extra)
 
+  def Unmount(self, mount_point):
+    self.script.append('unmount("%s");' % (mount_point,))
+    self.mounts.remove(mount_point);
+
   def UnmountAll(self):
     for p in sorted(self.mounts):
       self.script.append('unmount("%s");' % (p,))
diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index e8dff5a..755e5c2 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -37,6 +37,10 @@
       Generate an incremental OTA using the given target-files zip as
       the starting build.
 
+  -v  (--verify)
+      Remount and verify the checksums of the files written to the
+      system and vendor (if used) partitions.  Incremental builds only.
+
   -o  (--oem_settings)  <file>
       Use the file to specify the expected OEM-specific properties
       on the OEM partition of the intended device.
@@ -104,6 +108,7 @@
 OPTIONS = common.OPTIONS
 OPTIONS.package_key = None
 OPTIONS.incremental_source = None
+OPTIONS.verify = False
 OPTIONS.require_verbatim = set()
 OPTIONS.prohibit_verbatim = set(("system/build.prop",))
 OPTIONS.patch_threshold = 0.95
@@ -462,11 +467,12 @@
   script = edify_generator.EdifyGenerator(3, OPTIONS.info_dict)
 
   oem_props = OPTIONS.info_dict.get("oem_fingerprint_properties")
+  recovery_mount_options = OPTIONS.info_dict.get("recovery_mount_options")
   oem_dict = None
   if oem_props is not None and len(oem_props) > 0:
     if OPTIONS.oem_source is None:
       raise common.ExternalError("OEM source required for this build")
-    script.Mount("/oem")
+    script.Mount("/oem", recovery_mount_options)
     oem_dict = common.LoadDictionaryFromLines(open(OPTIONS.oem_source).readlines())
 
   metadata = {"post-build": CalculateFingerprint(
@@ -527,13 +533,13 @@
     bcb_dev = {"bcb_dev": fs.device}
     common.ZipWriteStr(output_zip, "recovery.img", recovery_img.data)
     script.AppendExtra("""
-if get_stage("%(bcb_dev)s", "stage") == "2/3" then
+if get_stage("%(bcb_dev)s") == "2/3" then
 """ % bcb_dev)
     script.WriteRawImage("/recovery", "recovery.img")
     script.AppendExtra("""
 set_stage("%(bcb_dev)s", "3/3");
 reboot_now("%(bcb_dev)s", "recovery");
-else if get_stage("%(bcb_dev)s", "stage") == "3/3" then
+else if get_stage("%(bcb_dev)s") == "3/3" then
 """ % bcb_dev)
 
   device_specific.FullOTA_InstallBegin()
@@ -548,6 +554,8 @@
   if "selinux_fc" in OPTIONS.info_dict:
     WritePolicyConfig(OPTIONS.info_dict["selinux_fc"], output_zip)
 
+  recovery_mount_options = OPTIONS.info_dict.get("recovery_mount_options")
+
   system_items = ItemSet("system", "META/filesystem_config.txt")
   script.ShowProgress(system_progress, 0)
   if block_based:
@@ -561,7 +569,7 @@
     system_diff.WriteScript(script, output_zip)
   else:
     script.FormatPartition("/system")
-    script.Mount("/system")
+    script.Mount("/system", recovery_mount_options)
     if not has_recovery_patch:
       script.UnpackPackageDir("recovery", "/system")
     script.UnpackPackageDir("system", "/system")
@@ -594,7 +602,7 @@
       vendor_diff.WriteScript(script, output_zip)
     else:
       script.FormatPartition("/vendor")
-      script.Mount("/vendor")
+      script.Mount("/vendor", recovery_mount_options)
       script.UnpackPackageDir("vendor", "/vendor")
 
       symlinks = CopyPartitionFiles(vendor_items, input_zip, output_zip)
@@ -745,11 +753,12 @@
     vendor_diff = None
 
   oem_props = OPTIONS.target_info_dict.get("oem_fingerprint_properties")
+  recovery_mount_options = OPTIONS.target_info_dict.get("recovery_mount_options")
   oem_dict = None
   if oem_props is not None and len(oem_props) > 0:
     if OPTIONS.oem_source is None:
       raise common.ExternalError("OEM source required for this build")
-    script.Mount("/oem")
+    script.Mount("/oem", recovery_mount_options)
     oem_dict = common.LoadDictionaryFromLines(open(OPTIONS.oem_source).readlines())
 
   AppendAssertions(script, OPTIONS.target_info_dict, oem_dict)
@@ -785,14 +794,14 @@
     bcb_dev = {"bcb_dev": fs.device}
     common.ZipWriteStr(output_zip, "recovery.img", target_recovery.data)
     script.AppendExtra("""
-if get_stage("%(bcb_dev)s", "stage") == "2/3" then
+if get_stage("%(bcb_dev)s") == "2/3" then
 """ % bcb_dev)
     script.AppendExtra("sleep(20);\n");
     script.WriteRawImage("/recovery", "recovery.img")
     script.AppendExtra("""
 set_stage("%(bcb_dev)s", "3/3");
 reboot_now("%(bcb_dev)s", "recovery");
-else if get_stage("%(bcb_dev)s", "stage") != "3/3" then
+else if get_stage("%(bcb_dev)s") != "3/3" then
 """ % bcb_dev)
 
   script.Print("Verifying current system...")
@@ -935,7 +944,7 @@
           raise common.ExternalError("\"%s\" must be sent verbatim" % (fn,))
         print "send", fn, "verbatim"
         tf.AddToZip(output_zip)
-        verbatim_targets.append((fn, tf.size))
+        verbatim_targets.append((fn, tf.size, tf.sha1))
         if fn in target_data.keys():
           AddToKnownPaths(fn, known_paths)
       elif tf.sha1 != sf.sha1:
@@ -956,7 +965,7 @@
         # or a patch + rename cannot take place due to the target
         # directory not existing
         tf.AddToZip(output_zip)
-        verbatim_targets.append((tf.name, tf.size))
+        verbatim_targets.append((tf.name, tf.size, tf.sha1))
         if sf.name in renames:
           del renames[sf.name]
         AddToKnownPaths(tf.name, known_paths)
@@ -976,6 +985,13 @@
       so_far += sf.size
     return so_far
 
+  def EmitExplicitTargetVerification(self, script):
+    for fn, size, sha1 in self.verbatim_targets:
+      if (fn[-1] != "/"):
+        script.FileCheck("/"+fn, sha1)
+    for tf, _, _, _ in self.patch_list:
+      script.FileCheck(tf.name, tf.sha1)
+
   def RemoveUnneededFiles(self, script, extras=()):
     script.DeleteFiles(["/"+i[0] for i in self.verbatim_targets] +
                        ["/"+i for i in sorted(self.source_data)
@@ -1035,11 +1051,12 @@
                                           OPTIONS.target_info_dict)
 
   oem_props = OPTIONS.info_dict.get("oem_fingerprint_properties")
+  recovery_mount_options = OPTIONS.info_dict.get("recovery_mount_options")
   oem_dict = None
   if oem_props is not None and len(oem_props) > 0:
     if OPTIONS.oem_source is None:
       raise common.ExternalError("OEM source required for this build")
-    script.Mount("/oem")
+    script.Mount("/oem", recovery_mount_options)
     oem_dict = common.LoadDictionaryFromLines(open(OPTIONS.oem_source).readlines())
 
   metadata = {"pre-device": GetOemProperty("ro.product.device", oem_props, oem_dict,
@@ -1059,10 +1076,10 @@
       info_dict=OPTIONS.info_dict)
 
   system_diff = FileDifference("system", source_zip, target_zip, output_zip)
-  script.Mount("/system")
+  script.Mount("/system", recovery_mount_options)
   if HasVendorPartition(target_zip):
     vendor_diff = FileDifference("vendor", source_zip, target_zip, output_zip)
-    script.Mount("/vendor")
+    script.Mount("/vendor", recovery_mount_options)
   else:
     vendor_diff = None
 
@@ -1133,14 +1150,14 @@
     bcb_dev = {"bcb_dev": fs.device}
     common.ZipWriteStr(output_zip, "recovery.img", target_recovery.data)
     script.AppendExtra("""
-if get_stage("%(bcb_dev)s", "stage") == "2/3" then
+if get_stage("%(bcb_dev)s") == "2/3" then
 """ % bcb_dev)
     script.AppendExtra("sleep(20);\n");
     script.WriteRawImage("/recovery", "recovery.img")
     script.AppendExtra("""
 set_stage("%(bcb_dev)s", "3/3");
 reboot_now("%(bcb_dev)s", "recovery");
-else if get_stage("%(bcb_dev)s", "stage") != "3/3" then
+else if get_stage("%(bcb_dev)s") != "3/3" then
 """ % bcb_dev)
 
   script.Print("Verifying current system...")
@@ -1346,7 +1363,19 @@
 endif;
 """ % bcb_dev)
 
+  if OPTIONS.verify and system_diff:
+    script.Print("Remounting and verifying system partition files...")
+    script.Unmount("/system")
+    script.Mount("/system")
+    system_diff.EmitExplicitTargetVerification(script)
+
+  if OPTIONS.verify and vendor_diff:
+    script.Print("Remounting and verifying vendor partition files...")
+    script.Unmount("/vendor")
+    script.Mount("/vendor")
+    vendor_diff.EmitExplicitTargetVerification(script)
   script.AddToZip(target_zip, output_zip, input_path=OPTIONS.updater_binary)
+
   WriteMetadata(metadata, output_zip)
 
 
@@ -1382,6 +1411,8 @@
       OPTIONS.two_step = True
     elif o == "--no_signing":
       OPTIONS.no_signing = True
+    elif o in ("--verify"):
+      OPTIONS.verify = True
     elif o == "--block":
       OPTIONS.block_based = True
     elif o in ("-b", "--binary"):
@@ -1407,6 +1438,7 @@
                                               "block",
                                               "binary=",
                                               "oem_settings=",
+                                              "verify",
                                               "no_fallback_to_full",
                                               ],
                              extra_option_handler=option_handler)
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()