Index: flang/runtime/io-stmt.h
===================================================================
--- flang/runtime/io-stmt.h
+++ flang/runtime/io-stmt.h
@@ -555,7 +555,7 @@
   std::optional<OpenStatus> status_;
   std::optional<Position> position_;
   std::optional<Action> action_;
-  Convert convert_{Convert::Native};
+  Convert convert_{Convert::Unknown};
   OwningPtr<char> path_;
   std::size_t pathLength_;
   std::optional<bool> isUnformatted_;
Index: flang/runtime/unit.cpp
===================================================================
--- flang/runtime/unit.cpp
+++ flang/runtime/unit.cpp
@@ -58,7 +58,7 @@
     IoErrorHandler handler{terminator};
     result->OpenAnonymousUnit(
         dir == Direction::Input ? OpenStatus::Unknown : OpenStatus::Replace,
-        Action::ReadWrite, Position::Rewind, Convert::Native, handler);
+        Action::ReadWrite, Position::Rewind, Convert::Unknown, handler);
     result->isUnformatted = isUnformatted;
   }
   return result;
@@ -92,7 +92,7 @@
 void ExternalFileUnit::OpenUnit(std::optional<OpenStatus> status,
     std::optional<Action> action, Position position, OwningPtr<char> &&newPath,
     std::size_t newPathLength, Convert convert, IoErrorHandler &handler) {
-  if (executionEnvironment.conversion != Convert::Unknown) {
+  if (convert == Convert::Unknown) {
     convert = executionEnvironment.conversion;
   }
   swapEndianness_ = convert == Convert::Swap ||