diff --git a/src/corelib/serialization/qdatastream.cpp b/src/corelib/serialization/qdatastream.cpp
index f1572b46c7..57713d3645 100644
--- a/src/corelib/serialization/qdatastream.cpp
+++ b/src/corelib/serialization/qdatastream.cpp
@@ -476,11 +476,14 @@ void QDataStream::setStatus(Status status)
 
 void QDataStream::setByteOrder(ByteOrder bo)
 {
+#if QT_VERSION < QT_VERSION_CHECK(7, 0, 0) && !defined(QT_BOOTSTRAPPED)
+    // accessed by inline byteOrder() prior to Qt 6.8
     byteorder = bo;
+#endif
     if (QSysInfo::ByteOrder == QSysInfo::BigEndian)
-        noswap = (byteorder == BigEndian);
+        noswap = (bo == BigEndian);
     else
-        noswap = (byteorder == LittleEndian);
+        noswap = (bo == LittleEndian);
 }
 
 
diff --git a/src/corelib/serialization/qdatastream.h b/src/corelib/serialization/qdatastream.h
index e7ef94a8a7..36d8a618ff 100644
--- a/src/corelib/serialization/qdatastream.h
+++ b/src/corelib/serialization/qdatastream.h
@@ -221,7 +221,9 @@ private:
     bool noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
     quint8 fpPrecision = QDataStream::DoublePrecision;
     quint8 q_status = Ok;
+#if QT_VERSION < QT_VERSION_CHECK(7, 0, 0) && !defined(QT_BOOTSTRAPPED)
     ByteOrder byteorder = BigEndian;
+#endif
     int ver = Qt_DefaultCompiledVersion;
     quint16 transactionDepth = 0;
 
@@ -438,7 +440,11 @@ QDataStream::FloatingPointPrecision QDataStream::floatingPointPrecision() const
 #endif // INLINE_SINCE 6.8
 
 inline QDataStream::ByteOrder QDataStream::byteOrder() const
-{ return byteorder; }
+{
+    if constexpr (QSysInfo::ByteOrder == QSysInfo::BigEndian)
+        return noswap ? BigEndian : LittleEndian;
+    return noswap ? LittleEndian : BigEndian;
+}
 
 inline int QDataStream::version() const
 { return ver; }