diff --git a/src/corelib/kernel/qcore_foundation.mm b/src/corelib/kernel/qcore_foundation.mm
index a31040944f1..6d2451e078e 100644
--- a/src/corelib/kernel/qcore_foundation.mm
+++ b/src/corelib/kernel/qcore_foundation.mm
@@ -300,8 +300,8 @@ QUuid QUuid::fromCFUUID(CFUUIDRef uuid)
 */
 CFUUIDRef QUuid::toCFUUID() const
 {
-    const QByteArray bytes = toRfc4122();
-    return CFUUIDCreateFromUUIDBytes(0, *reinterpret_cast<const CFUUIDBytes *>(bytes.constData()));
+    const auto bytes = toBytes();
+    return CFUUIDCreateFromUUIDBytes(0, *reinterpret_cast<const CFUUIDBytes *>(&bytes));
 }
 
 /*!
@@ -333,8 +333,11 @@ QUuid QUuid::fromNSUUID(const NSUUID *uuid)
 */
 NSUUID *QUuid::toNSUUID() const
 {
-    const QByteArray bytes = toRfc4122();
-    return [[[NSUUID alloc] initWithUUIDBytes:*reinterpret_cast<const uuid_t *>(bytes.constData())] autorelease];
+    const auto bytes = toBytes();
+    static_assert(sizeof bytes == sizeof(uuid_t));
+    uuid_t u;
+    memcpy(&u, &bytes, sizeof(uuid_t));
+    return [[[NSUUID alloc] initWithUUIDBytes:u] autorelease];
 }
 
 // ----------------------------------------------------------------------------
diff --git a/src/corelib/plugin/quuid.cpp b/src/corelib/plugin/quuid.cpp
index 42f21eea88c..8c3b758aaca 100644
--- a/src/corelib/plugin/quuid.cpp
+++ b/src/corelib/plugin/quuid.cpp
@@ -119,7 +119,7 @@ static QUuid _q_uuidFromHex(const char *src)
 static QUuid createFromName(const QUuid &ns, const QByteArray &baseData, QCryptographicHash::Algorithm algorithm, int version)
 {
     QCryptographicHash hash(algorithm);
-    hash.addData(ns.toRfc4122());
+    hash.addData(QByteArrayView{ns.toBytes()});
     hash.addData(baseData);
     QByteArrayView hashResult = hash.resultView();
     Q_ASSERT(hashResult.size() >= 16);