diff --git a/library/ecp.c b/library/ecp.c
index 1a83ed0..d2d2e18 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -604,7 +604,7 @@
 #endif /* POLARSSL_ECP_DP_SECP521R1_ENABLED */
     }
 
-    return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
+    return( POLARSSL_ERR_ECP_FEATURE_UNAVAILABLE );
 }
 
 /*