diff --git a/core/Makefile b/core/Makefile
index a81c981..97a3f08 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -604,21 +604,19 @@
 ifeq ($(INTERNAL_USERIMAGES_USE_EXT),true)
 INTERNAL_USERIMAGES_DEPS := $(MKEXTUSERIMG) $(MAKE_EXT4FS)
 INTERNAL_USERIMAGES_BINARY_PATHS := $(sort $(dir $(INTERNAL_USERIMAGES_DEPS)))
-
-# $(1): src directory
-# $(2): output file
-# $(3): mount point
-# $(4): ext variant (ext2, ext3, ext4)
-# $(5): size of the partition
-define build-userimage-ext-target
-  @mkdir -p $(dir $(2))
-  $(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH \
-	  $(MKEXTUSERIMG) $(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG) $(1) $(2) $(4) $(3) $(5)
-endef
 else
 INTERNAL_USERIMAGES_DEPS := $(MKYAFFS2)
 endif
 
+# $(1): the path of the output dictionary file
+define generate-userimage-prop-dictionary
+$(if $(INTERNAL_USERIMAGES_EXT_VARIANT),$(hide) echo "fs_type=$(INTERNAL_USERIMAGES_EXT_VARIANT)" >> $(1))
+$(if $(BOARD_SYSTEMIMAGE_PARTITION_SIZE),$(hide) echo "system_size=$(BOARD_SYSTEMIMAGE_PARTITION_SIZE)" >> $(1))
+$(if $(BOARD_USERDATAIMAGE_PARTITION_SIZE),$(hide) echo "userdata_size=$(BOARD_USERDATAIMAGE_PARTITION_SIZE)" >> $(1))
+$(if $(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG),$(hide) echo "extfs_sparse_flag=$(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG)" >> $(1))
+$(if $(mkyaffs2_extra_flags),$(hide) echo "mkyaffs2_extra_flags=$(mkyaffs2_extra_flags)" >> $(1))
+endef
+
 # -----------------------------------------------------------------
 # Recovery image
 
@@ -772,25 +770,16 @@
 	$(call intermediates-dir-for,PACKAGING,systemimage)
 BUILT_SYSTEMIMAGE := $(systemimage_intermediates)/system.img
 
-ifeq ($(INTERNAL_USERIMAGES_USE_EXT),true)
-## generate an ext image
 # $(1): output file
 define build-systemimage-target
-    @echo "Target system fs image: $(1)"
-    $(call build-userimage-ext-target,$(TARGET_OUT),$(1),system,$(INTERNAL_USERIMAGES_EXT_VARIANT),$(BOARD_SYSTEMIMAGE_PARTITION_SIZE))
+  @echo "Target system fs image: $(1)"
+  @mkdir -p $(dir $(1)) $(systemimage_intermediates) && rm -rf $(systemimage_intermediates)/system_image_info.txt
+  $(call generate-userimage-prop-dictionary, $(systemimage_intermediates)/system_image_info.txt)
+  $(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH \
+      ./build/tools/releasetools/build_image.py \
+      $(TARGET_OUT) $(systemimage_intermediates)/system_image_info.txt $(1)
 endef
 
-else # INTERNAL_USERIMAGES_USE_EXT != true
-
-## generate a yaffs2 image
-# $(1): output file
-define build-systemimage-target
-    @echo "Target system fs image: $(1)"
-    @mkdir -p $(dir $(1))
-    $(hide) $(MKYAFFS2) -f $(mkyaffs2_extra_flags) $(TARGET_OUT) $(1)
-endef
-endif # INTERNAL_USERIMAGES_USE_EXT
-
 $(BUILT_SYSTEMIMAGE): $(FULL_SYSTEMIMAGE_DEPS) $(INSTALLED_FILES_FILE)
 	$(call build-systemimage-target,$@)
 
@@ -890,28 +879,21 @@
 INTERNAL_USERDATAIMAGE_FILES := \
 	$(filter $(TARGET_OUT_DATA)/%,$(ALL_DEFAULT_INSTALLED_MODULES))
 
-ifeq ($(INTERNAL_USERIMAGES_USE_EXT),true)
-## Generate an ext2 image
-define build-userdataimage-target
-    $(call pretty,"Target userdata fs image: $(INSTALLED_USERDATAIMAGE_TARGET)")
-    @mkdir -p $(TARGET_OUT_DATA)
-    $(call build-userimage-ext-target,$(TARGET_OUT_DATA),$(INSTALLED_USERDATAIMAGE_TARGET),data,$(INTERNAL_USERIMAGES_EXT_VARIANT),$(BOARD_USERDATAIMAGE_PARTITION_SIZE))
-    $(hide) $(call assert-max-image-size,$(INSTALLED_USERDATAIMAGE_TARGET),$(BOARD_USERDATAIMAGE_PARTITION_SIZE),yaffs)
-endef
-
-else # INTERNAL_USERIMAGES_USE_EXT != true
-
-## Generate a yaffs2 image
-define build-userdataimage-target
-    $(call pretty,"Target userdata fs image: $(INSTALLED_USERDATAIMAGE_TARGET)")
-    @mkdir -p $(TARGET_OUT_DATA)
-    $(hide) $(MKYAFFS2) -f $(mkyaffs2_extra_flags) $(TARGET_OUT_DATA) $(INSTALLED_USERDATAIMAGE_TARGET)
-    $(hide) $(call assert-max-image-size,$(INSTALLED_USERDATAIMAGE_TARGET),$(BOARD_USERDATAIMAGE_PARTITION_SIZE),yaffs)
-endef
-endif # INTERNAL_USERIMAGES_USE_EXT
-
+userdataimage_intermediates := \
+	$(call intermediates-dir-for,PACKAGING,userdata)
 BUILT_USERDATAIMAGE_TARGET := $(PRODUCT_OUT)/userdata.img
 
+define build-userdataimage-target
+  $(call pretty,"Target userdata fs image: $(INSTALLED_USERDATAIMAGE_TARGET)")
+  @mkdir -p $(TARGET_OUT_DATA)
+  @mkdir -p $(userdataimage_intermediates) && rm -rf $(userdataimage_intermediates)/userdata_image_info.txt
+  $(call generate-userimage-prop-dictionary, $(userdataimage_intermediates)/userdata_image_info.txt)
+  $(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH \
+      ./build/tools/releasetools/build_image.py \
+      $(TARGET_OUT_DATA) $(userdataimage_intermediates)/userdata_image_info.txt $@
+  $(hide) $(call assert-max-image-size,$(INSTALLED_USERDATAIMAGE_TARGET),$(BOARD_USERDATAIMAGE_PARTITION_SIZE),yaffs)
+endef
+
 # We just build this directly to the install location.
 INSTALLED_USERDATAIMAGE_TARGET := $(BUILT_USERDATAIMAGE_TARGET)
 $(INSTALLED_USERDATAIMAGE_TARGET): $(INTERNAL_USERIMAGES_DEPS) \
@@ -1100,23 +1082,12 @@
 ifdef BOARD_RECOVERYIMAGE_PARTITION_SIZE
 	$(hide) echo "recovery_size=$(BOARD_RECOVERYIMAGE_PARTITION_SIZE)" >> $(zip_root)/META/misc_info.txt
 endif
-ifdef BOARD_SYSTEMIMAGE_PARTITION_SIZE
-	$(hide) echo "system_size=$(BOARD_SYSTEMIMAGE_PARTITION_SIZE)" >> $(zip_root)/META/misc_info.txt
-endif
-ifdef BOARD_USERDATAIMAGE_PARTITION_SIZE
-	$(hide) echo "userdata_size=$(BOARD_USERDATAIMAGE_PARTITION_SIZE)" >> $(zip_root)/META/misc_info.txt
-endif
 	$(hide) echo "tool_extensions=$(tool_extensions)" >> $(zip_root)/META/misc_info.txt
-ifdef mkyaffs2_extra_flags
-	$(hide) echo "mkyaffs2_extra_flags=$(mkyaffs2_extra_flags)" >> $(zip_root)/META/misc_info.txt
-endif
-ifdef INTERNAL_USERIMAGES_SPARSE_EXT_FLAG
-	$(hide) echo "extfs_sparse_flag=$(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG)" >> $(zip_root)/META/misc_info.txt
-endif
 	$(hide) echo "default_system_dev_certificate=$(DEFAULT_SYSTEM_DEV_CERTIFICATE)" >> $(zip_root)/META/misc_info.txt
 ifdef PRODUCT_EXTRA_RECOVERY_KEYS
 	$(hide) echo "extra_recovery_keys=$(PRODUCT_EXTRA_RECOVERY_KEYS)" >> $(zip_root)/META/misc_info.txt
 endif
+	$(call generate-userimage-prop-dictionary, $(zip_root)/META/misc_info.txt)
 	@# Zip everything up, preserving symlinks
 	$(hide) (cd $(zip_root) && zip -qry ../$(notdir $@) .)
 	@# Run fs_config on all the system, boot ramdisk, and recovery ramdisk files in the zip, and save the output