diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index af64955..3e159a6 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -428,9 +428,8 @@
 def SetUpInDirAndFsConfig(origin_in, prop_dict):
   """Returns the in_dir and fs_config that should be used for image building.
 
-  If the target uses system_root_image and it's building system.img, it creates
-  and returns a staged dir that combines the contents of /system (i.e. in the
-  given in_dir) and root.
+  When building system.img for all targets, it creates and returns a staged dir
+  that combines the contents of /system (i.e. in the given in_dir) and root.
 
   Args:
     origin_in: Path to the input directory.
@@ -441,8 +440,12 @@
     A tuple of in_dir and fs_config that should be used to build the image.
   """
   fs_config = prop_dict.get("fs_config")
-  if (prop_dict.get("system_root_image") != "true" or
-      prop_dict["mount_point"] != "system"):
+
+  if prop_dict["mount_point"] == "system_other":
+    prop_dict["mount_point"] = "system"
+    return origin_in, fs_config
+
+  if prop_dict["mount_point"] != "system":
     return origin_in, fs_config
 
   # Construct a staging directory of the root file system.
@@ -516,9 +519,6 @@
 def BuildImage(in_dir, prop_dict, out_file, target_out=None):
   """Builds an image for the files under in_dir and writes it to out_file.
 
-  When using system_root_image, it will additionally look for the files under
-  root (specified by 'root_dir') and builds an image that contains both sources.
-
   Args:
     in_dir: Path to input directory.
     prop_dict: A property dict that contains info like partition size. Values
@@ -838,7 +838,6 @@
   elif mount_point == "system_other":
     # We inherit the selinux policies of /system since we contain some of its
     # files.
-    d["mount_point"] = "system"
     copy_prop("avb_system_hashtree_enable", "avb_hashtree_enable")
     copy_prop("avb_system_add_hashtree_footer_args",
               "avb_add_hashtree_footer_args")