diff --git a/core/Makefile b/core/Makefile
index 5423322..bb97c56 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -783,6 +783,8 @@
 SELINUX_FC := $(TARGET_ROOT_OUT)/file_contexts.bin
 INTERNAL_USERIMAGES_DEPS += $(SELINUX_FC)
 
+INTERNAL_USERIMAGES_DEPS += $(BLK_ALLOC_TO_BASE_FS)
+
 # $(1): the path of the output dictionary file
 # $(2): additional "key=value" pairs to append to the dictionary file.
 define generate-userimage-prop-dictionary
@@ -793,6 +795,7 @@
 $(if $(BOARD_HAS_EXT4_RESERVED_BLOCKS),$(hide) echo "has_ext4_reserved_blocks=$(BOARD_HAS_EXT4_RESERVED_BLOCKS)" >> $(1))
 $(if $(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR),$(hide) echo "system_squashfs_compressor=$(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR)" >> $(1))
 $(if $(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR_OPT),$(hide) echo "system_squashfs_compressor_opt=$(BOARD_SYSTEMIMAGE_SQUASHFS_COMPRESSOR_OPT)" >> $(1))
+$(if $(INTERNAL_SYSTEM_BASE_FS_PATH),$(hide) echo "system_base_fs_file=$(INTERNAL_SYSTEM_BASE_FS_PATH)" >> $(1))
 $(if $(BOARD_USERDATAIMAGE_FILE_SYSTEM_TYPE),$(hide) echo "userdata_fs_type=$(BOARD_USERDATAIMAGE_FILE_SYSTEM_TYPE)" >> $(1))
 $(if $(BOARD_USERDATAIMAGE_PARTITION_SIZE),$(hide) echo "userdata_size=$(BOARD_USERDATAIMAGE_PARTITION_SIZE)" >> $(1))
 $(if $(BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE),$(hide) echo "cache_fs_type=$(BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE)" >> $(1))
@@ -802,6 +805,7 @@
 $(if $(BOARD_VENDORIMAGE_JOURNAL_SIZE),$(hide) echo "vendor_journal_size=$(BOARD_VENDORIMAGE_JOURNAL_SIZE)" >> $(1))
 $(if $(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR),$(hide) echo "vendor_squashfs_compressor=$(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR)" >> $(1))
 $(if $(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR_OPT),$(hide) echo "vendor_squashfs_compressor_opt=$(BOARD_VENDORIMAGE_SQUASHFS_COMPRESSOR_OPT)" >> $(1))
+$(if $(INTERNAL_VENDOR_BASE_FS_PATH),$(hide) echo "vendor_base_fs_file=$(INTERNAL_VENDOR_BASE_FS_PATH)" >> $(1))
 $(if $(BOARD_OEMIMAGE_PARTITION_SIZE),$(hide) echo "oem_size=$(BOARD_OEMIMAGE_PARTITION_SIZE)" >> $(1))
 $(if $(BOARD_OEMIMAGE_JOURNAL_SIZE),$(hide) echo "oem_journal_size=$(BOARD_OEMIMAGE_JOURNAL_SIZE)" >> $(1))
 $(if $(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG),$(hide) echo "extfs_sparse_flag=$(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG)" >> $(1))
diff --git a/core/config.mk b/core/config.mk
index bae2168..1130b1b 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -526,6 +526,7 @@
 APICHECK := $(HOST_OUT_EXECUTABLES)/apicheck$(HOST_EXECUTABLE_SUFFIX)
 FS_GET_STATS := $(HOST_OUT_EXECUTABLES)/fs_get_stats$(HOST_EXECUTABLE_SUFFIX)
 MAKE_EXT4FS := $(HOST_OUT_EXECUTABLES)/make_ext4fs$(HOST_EXECUTABLE_SUFFIX)
+BLK_ALLOC_TO_BASE_FS := $(HOST_OUT_EXECUTABLES)/blk_alloc_to_base_fs$(HOST_EXECUTABLE_SUFFIX)
 MKEXTUSERIMG := $(HOST_OUT_EXECUTABLES)/mkuserimg.sh
 ifeq ($(HOST_OS),linux)
 MAKE_SQUASHFS := $(HOST_OUT_EXECUTABLES)/mksquashfs$(HOST_EXECUTABLE_SUFFIX)
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 5cdede7..f35369f 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -292,6 +292,18 @@
   shutil.rmtree(tempdir_name, ignore_errors=True)
   return True
 
+def ConvertBlockMapToBaseFs(block_map_file):
+  fd, base_fs_file = tempfile.mkstemp(prefix="script_gen_",
+                                      suffix=".base_fs")
+  os.close(fd)
+
+  convert_command = ["blk_alloc_to_base_fs", block_map_file, base_fs_file]
+  (_, exit_code) = RunCommand(convert_command)
+  if exit_code != 0:
+    os.remove(base_fs_file)
+    return None
+  return base_fs_file
+
 def BuildImage(in_dir, prop_dict, out_file, target_out=None):
   """Build an image to out_file from in_dir with property prop_dict.
 
@@ -308,6 +320,7 @@
   # /system and the ramdisk, and can be mounted at the root of the file system.
   origin_in = in_dir
   fs_config = prop_dict.get("fs_config")
+  base_fs_file = None
   if (prop_dict.get("system_root_image") == "true"
       and prop_dict["mount_point"] == "system"):
     in_dir = tempfile.mkdtemp()
@@ -367,6 +380,11 @@
       build_command.extend(["-D", target_out])
     if "block_list" in prop_dict:
       build_command.extend(["-B", prop_dict["block_list"]])
+    if "base_fs_file" in prop_dict:
+      base_fs_file = ConvertBlockMapToBaseFs(prop_dict["base_fs_file"])
+      if base_fs_file is None:
+        return False
+      build_command.extend(["-d", base_fs_file])
     build_command.extend(["-L", prop_dict["mount_point"]])
     if "selinux_fc" in prop_dict:
       build_command.append(prop_dict["selinux_fc"])
@@ -421,6 +439,8 @@
       shutil.rmtree(in_dir, ignore_errors=True)
       if fs_config:
         os.remove(fs_config)
+    if base_fs_file is not None:
+      os.remove(base_fs_file)
   if exit_code != 0:
     return False
 
@@ -525,6 +545,7 @@
     copy_prop("has_ext4_reserved_blocks", "has_ext4_reserved_blocks")
     copy_prop("system_squashfs_compressor", "squashfs_compressor")
     copy_prop("system_squashfs_compressor_opt", "squashfs_compressor_opt")
+    copy_prop("system_base_fs_file", "base_fs_file")
   elif mount_point == "data":
     # Copy the generic fs type first, override with specific one if available.
     copy_prop("fs_type", "fs_type")
@@ -541,6 +562,7 @@
     copy_prop("has_ext4_reserved_blocks", "has_ext4_reserved_blocks")
     copy_prop("vendor_squashfs_compressor", "squashfs_compressor")
     copy_prop("vendor_squashfs_compressor_opt", "squashfs_compressor_opt")
+    copy_prop("vendor_base_fs_file", "base_fs_file")
   elif mount_point == "oem":
     copy_prop("fs_type", "fs_type")
     copy_prop("oem_size", "partition_size")