diff --git a/tools/fs_config/Android.mk b/tools/fs_config/Android.mk
index f946303..a01e702 100644
--- a/tools/fs_config/Android.mk
+++ b/tools/fs_config/Android.mk
@@ -254,7 +254,7 @@
 include $(BUILD_HEADER_LIBRARY)
 
 ##################################
-# Generate the system/etc/passwd text file for the target
+# Generate the vendor/etc/passwd text file for the target
 # This file may be empty if no AIDs are defined in
 # TARGET_FS_CONFIG_GEN files.
 include $(CLEAR_VARS)
@@ -270,10 +270,10 @@
 $(LOCAL_BUILT_MODULE): PRIVATE_ANDROID_FS_HDR := $(system_android_filesystem_config)
 $(LOCAL_BUILT_MODULE): $(LOCAL_PATH)/fs_config_generator.py $(TARGET_FS_CONFIG_GEN) $(system_android_filesystem_config)
 	@mkdir -p $(dir $@)
-	$(hide) $< passwd --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
+	$(hide) $< passwd --required-prefix=vendor_ --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
 
 ##################################
-# Generate the system/etc/group text file for the target
+# Generate the vendor/etc/group text file for the target
 # This file may be empty if no AIDs are defined in
 # TARGET_FS_CONFIG_GEN files.
 include $(CLEAR_VARS)
@@ -289,7 +289,7 @@
 $(LOCAL_BUILT_MODULE): PRIVATE_ANDROID_FS_HDR := $(system_android_filesystem_config)
 $(LOCAL_BUILT_MODULE): $(LOCAL_PATH)/fs_config_generator.py $(TARGET_FS_CONFIG_GEN) $(system_android_filesystem_config)
 	@mkdir -p $(dir $@)
-	$(hide) $< group --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
+	$(hide) $< group --required-prefix=vendor_ --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
 
 system_android_filesystem_config :=
 endif
diff --git a/tools/fs_config/fs_config_generator.py b/tools/fs_config/fs_config_generator.py
index d51d075..ed63c0e 100755
--- a/tools/fs_config/fs_config_generator.py
+++ b/tools/fs_config/fs_config_generator.py
@@ -1235,12 +1235,19 @@
             help='An android_filesystem_config.h file'
             'to parse AIDs and OEM Ranges from')
 
+        opt_group.add_argument(
+            '--required-prefix',
+            required=False,
+            help='A prefix that the names are required to contain.')
+
     def __call__(self, args):
 
         hdr_parser = AIDHeaderParser(args['aid_header'])
 
         parser = FSConfigFileParser(args['fsconfig'], hdr_parser.oem_ranges)
 
+        required_prefix = args['required_prefix']
+
         aids = parser.aids
 
         # nothing to do if no aids defined
@@ -1250,7 +1257,11 @@
         print PasswdGen._GENERATED
 
         for aid in aids:
-            self._print_formatted_line(aid)
+            if required_prefix is None or aid.friendly.startswith(required_prefix):
+                self._print_formatted_line(aid)
+            else:
+                sys.exit("%s: AID '%s' must start with '%s'" %
+                         (args['fsconfig'], aid.friendly, required_prefix))
 
     def _print_formatted_line(self, aid):
         """Prints the aid to stdout in the passwd format. Internal use only.