diff --git a/src/lib.rs b/src/lib.rs
index 91a8d68..280e601 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -435,4 +435,31 @@ mod test {
         let test5 = Test::from_bytes(&mut cur);
         assert!(test5 == Err(PacketParseError::NotEnoughBytes));
     }
+
+    #[test]
+    fn test_pso_packet_manual_flag() {
+        #[pso_packet(0x23, manual_flag)]
+        struct Test {
+            flag: u32,
+            a: u32,
+            b: u32,
+        }
+
+        let test = Test {
+            flag: 99,
+            a: 123,
+            b: 456,
+        };
+
+        let mut bytes = test.as_bytes();
+        assert!(bytes == vec![16, 0, 35, 0, 99, 0, 0, 0, 123, 0, 0, 0, 200, 1, 0, 0]);
+
+        bytes[6] = 2;
+        let test2 = Test::from_bytes(&bytes).unwrap();
+        assert!(test2 == Test {
+            flag: 131171,
+            a: 123,
+            b: 456,
+        });
+    }
 }