diff --git a/core/Makefile b/core/Makefile
index e11234e..29c4043 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -566,8 +566,12 @@
 endif
 endif
 
+ifneq (true,$(TARGET_USERIMAGES_SPARSE_EXT_DISABLED))
+  INTERNAL_USERIMAGES_SPARSE_EXT_FLAG := -s
+endif
+
 ifeq ($(INTERNAL_USERIMAGES_USE_EXT),true)
-INTERNAL_USERIMAGES_DEPS := $(MKEXT2USERIMG) $(MAKE_EXT4FS)
+INTERNAL_USERIMAGES_DEPS := $(MKEXTUSERIMG) $(MAKE_EXT4FS)
 INTERNAL_USERIMAGES_BINARY_PATHS := $(sort $(dir $(INTERNAL_USERIMAGES_DEPS)))
 
 # $(1): src directory
@@ -577,8 +581,8 @@
 # $(5): size of the partition
 define build-userimage-ext-target
   @mkdir -p $(dir $(2))
-    $(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$(PATH) \
-	  $(MKEXT2USERIMG) $(1) $(2) $(4) $(3) $(5)
+  $(hide) PATH=$(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)
@@ -1044,6 +1048,9 @@
 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
 	@# Zip everything up, preserving symlinks
 	$(hide) (cd $(zip_root) && zip -qry ../$(notdir $@) .)
 	@# Run fs_config on all the system files in the zip, and save the output
diff --git a/core/config.mk b/core/config.mk
index 0dec4be..1282ad6 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -210,7 +210,7 @@
 FS_GET_STATS := $(HOST_OUT_EXECUTABLES)/fs_get_stats$(HOST_EXECUTABLE_SUFFIX)
 MKEXT2IMG := $(HOST_OUT_EXECUTABLES)/genext2fs$(HOST_EXECUTABLE_SUFFIX)
 MAKE_EXT4FS := $(HOST_OUT_EXECUTABLES)/make_ext4fs$(HOST_EXECUTABLE_SUFFIX)
-MKEXT2USERIMG := $(HOST_OUT_EXECUTABLES)/mkuserimg.sh
+MKEXTUSERIMG := $(HOST_OUT_EXECUTABLES)/mkuserimg.sh
 MKEXT2BOOTIMG := external/genext2fs/mkbootimg_ext2.sh
 MKTARBALL := build/tools/mktarball.sh
 TUNE2FS := tune2fs
diff --git a/tools/releasetools/img_from_target_files b/tools/releasetools/img_from_target_files
index f10af49..0139916 100755
--- a/tools/releasetools/img_from_target_files
+++ b/tools/releasetools/img_from_target_files
@@ -61,10 +61,13 @@
   img = tempfile.NamedTemporaryFile()
 
   build_command = []
-  if OPTIONS.info_dict["fstab"]["/data"].fs_type.startswith("ext"):
-    build_command = ["mkuserimg.sh",
-                     user_dir, img.name,
-                     OPTIONS.info_dict["fstab"]["/data"].fs_type, "data"]
+  fstab = OPTIONS.info_dict["fstab"]
+  if fstab and fstab["/data"].fs_type.startswith("ext"):
+    build_command = ["mkuserimg.sh"]
+    if "extfs_sparse_flag" in OPTIONS.info_dict:
+      build_command.append(OPTIONS.info_dict["extfs_sparse_flag"])
+    build_command.extend([user_dir, img.name,
+                     fstab["/data"].fs_type, "data"])
     if "userdata_size" in OPTIONS.info_dict:
       build_command.append(str(OPTIONS.info_dict["userdata_size"]))
   else:
@@ -109,10 +112,14 @@
       pass
 
   build_command = []
-  if OPTIONS.info_dict["fstab"]["/system"].fs_type.startswith("ext"):
-    build_command = ["mkuserimg.sh",
-                     os.path.join(OPTIONS.input_tmp, "system"), img.name,
-                     OPTIONS.info_dict["fstab"]["/system"].fs_type, "system"]
+  fstab = OPTIONS.info_dict["fstab"]
+  if fstab and fstab["/system"].fs_type.startswith("ext"):
+
+    build_command = ["mkuserimg.sh"]
+    if "extfs_sparse_flag" in OPTIONS.info_dict:
+      build_command.append(OPTIONS.info_dict["extfs_sparse_flag"])
+    build_command.extend([os.path.join(OPTIONS.input_tmp, "system"), img.name,
+                     fstab["/system"].fs_type, "system"])
     if "system_size" in OPTIONS.info_dict:
       build_command.append(str(OPTIONS.info_dict["system_size"]))
   else: