diff --git a/gowin/arch.cc b/gowin/arch.cc
index 438c6ca9..e4dce329 100644
--- a/gowin/arch.cc
+++ b/gowin/arch.cc
@@ -520,7 +520,7 @@ void Arch::read_cst(std::istream &in)
             std::string attr = "&";
             attr += match[2];
             boost::algorithm::to_upper(attr);
-            it->second->attrs[id(attr)] = 0;
+            it->second->attrs[id(attr)] = 1;
         }
     }
 }