diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index 941ac69..dcc7073 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -836,7 +836,7 @@
 #endif /* MBEDTLS_ECP_DP_CURVE448_ENABLED */
 
         default:
-            grp->id = 0;
+            grp->id = MBEDTLS_ECP_DP_NONE;
             return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
     }
 }