diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 13c5363..c1e43b2 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -357,6 +357,7 @@
     if (needs_compress or prop_dict.get("system_fs_compress") == "true"):
       build_command.append("--compression")
     if (prop_dict.get("system_fs_compress") == "true"):
+      build_command.append("--readonly")
       build_command.append("--sldc")
       if (prop_dict.get("system_f2fs_sldc_flags") == None):
         build_command.append(str(0))