diff --git a/tests/test_msg_ripple_sign_tx.py b/tests/test_msg_ripple_sign_tx.py
index aaeab6cd..4a68d4b9 100644
--- a/tests/test_msg_ripple_sign_tx.py
+++ b/tests/test_msg_ripple_sign_tx.py
@@ -165,6 +165,23 @@ def test_sign_with_thorchain_memo(self):
             "plain send must not contain Memos array (0xF9 0xEA marker sequence)"
         )
 
+    def test_unsupported_memo_is_rejected(self):
+        self.requires_fullFeature()
+        self.requires_firmware("7.14.3")
+        if self.firmware_at_least("7.15.0"):
+            self.skipTest("Ripple memos are implemented in 7.15")
+        self.setup_mnemonic_allallall()
+        msg = messages.RippleSignTx(
+            address_n=parse_path("m/44'/144'/0'/0/0"),
+            payment=messages.RipplePayment(
+                amount=100000000,
+                destination="rBKz5MC2iXdoS3XgnNSYmF69K1Yo4NS3Ws"),
+            flags=0x80000000, fee=100000, sequence=25,
+            memo="routing-memo")
+        with self.assertRaises(CallException) as caught:
+            self.client.call(msg)
+        self.assertEqual(caught.exception.args[0], types.Failure_SyntaxError)
+
     def test_ripple_sign_invalid_fee(self):
         self.requires_fullFeature()
         self.requires_firmware("6.4.0")