diff --git a/bin/flutter b/bin/flutter
index e0c18e23584..cdf97423320 100755
--- a/bin/flutter
+++ b/bin/flutter
@@ -127,7 +127,7 @@ function upgrade_flutter () {
 
     retry_upgrade
 
-    "$DART" $FLUTTER_TOOL_ARGS --snapshot="$SNAPSHOT_PATH" --packages="$FLUTTER_TOOLS_DIR/.packages" "$SCRIPT_PATH"
+    "$DART" $FLUTTER_TOOL_ARGS --snapshot="$SNAPSHOT_PATH" --packages="$FLUTTER_TOOLS_DIR/.packages" --no-enable-mirrors "$SCRIPT_PATH"
     echo "$revision" > "$STAMP_PATH"
   fi
   # The exit here is duplicitous since the function is run in a subshell,
diff --git a/bin/flutter.bat b/bin/flutter.bat
index efe6c9c38f1..e97df639212 100644
--- a/bin/flutter.bat
+++ b/bin/flutter.bat
@@ -152,7 +152,7 @@ GOTO :after_subroutine
     POPD
 
     IF "%FLUTTER_TOOL_ARGS%" == "" (
-      "%dart%" --snapshot="%snapshot_path%" --packages="%flutter_tools_dir%\.packages" "%script_path%"
+      "%dart%" --snapshot="%snapshot_path%" --packages="%flutter_tools_dir%\.packages" --no-enable-mirrors "%script_path%"
     ) else (
       "%dart%" "%FLUTTER_TOOL_ARGS%" --snapshot="%snapshot_path%" --packages="%flutter_tools_dir%\.packages" "%script_path%"
     )