diff --git a/test/test/spec/main_spec.rb b/test/test/spec/main_spec.rb
index 5c636721..93dc548e 100644
--- a/test/test/spec/main_spec.rb
+++ b/test/test/spec/main_spec.rb
@@ -237,3 +237,11 @@ describe "Properties implemented using forwarders" do
     mr.inviteMessage.should == 'welcome to hell'
   end
 end
+
+describe "NSNotFound" do
+  # RM-491
+  it "can be retrieved with method return value" do
+    num = NSNumber.numberWithUnsignedInteger(NSNotFound)
+    num.unsignedIntegerValue.should == NSNotFound
+  end
+end
diff --git a/vm b/vm
index 668cfa74..590a7428 160000
--- a/vm
+++ b/vm
@@ -1 +1 @@
-Subproject commit 668cfa74351aa31869b9a4f372070748b49d0afe
+Subproject commit 590a74288c2693cd19a1762d4d32dafecf077186