diff --git a/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp b/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp
index b94c056a799..e6b787ccf7c 100644
--- a/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp
+++ b/src/plugins/platforms/qnx/qqnxrasterbackingstore.cpp
@@ -7,6 +7,7 @@
 #include "qqnxglobal.h"
 
 #include <QtCore/QDebug>
+#include <QtGui/QBackingStore>
 
 #include <errno.h>
 
@@ -74,7 +75,14 @@ bool QQnxRasterBackingStore::scroll(const QRegion &area, int dx, int dy)
     m_needsPosting = true;
 
     if (!m_scrolled) {
+#if defined(QQNX_INCREMENTAL_RASTER_UPDATE)
         platformWindow()->scroll(area, dx, dy, true);
+#else
+        platformWindow()->scroll(area, dx, dy, false);
+        QRegion remainder = QRect(QPoint(0, 0), backingStore()->size());
+        remainder -= area.translated(dx, dy);
+        platformWindow()->scroll(remainder, 0, 0, true);
+#endif
         m_scrolled = true;
         return true;
     }
@@ -90,6 +98,7 @@ void QQnxRasterBackingStore::beginPaint(const QRegion &region)
 
     platformWindow()->adjustBufferSize();
 
+#if defined(QQNX_INCREMENTAL_RASTER_UPDATE)
     if (window()->requestedFormat().alphaBufferSize() > 0) {
         auto platformScreen = static_cast<QQnxScreen *>(platformWindow()->screen());
         for (const QRect &r : region) {
@@ -109,6 +118,10 @@ void QQnxRasterBackingStore::beginPaint(const QRegion &region)
         Q_SCREEN_CHECKERROR(screen_flush_blits(platformScreen->nativeContext(),
                     SCREEN_WAIT_IDLE), "failed to flush blits");
     }
+#else
+    if (!m_scrolled)
+        platformWindow()->scroll(QRect(QPoint(0, 0), backingStore()->size()), 0, 0, true);
+#endif
 }
 
 void QQnxRasterBackingStore::endPaint()
diff --git a/src/plugins/platforms/qnx/qqnxrasterwindow.cpp b/src/plugins/platforms/qnx/qqnxrasterwindow.cpp
index 303c9e7c064..72442035b40 100644
--- a/src/plugins/platforms/qnx/qqnxrasterwindow.cpp
+++ b/src/plugins/platforms/qnx/qqnxrasterwindow.cpp
@@ -58,6 +58,7 @@ void QQnxRasterWindow::post(const QRegion &dirty)
         qCDebug(lcQpaWindow) << Q_FUNC_INFO << "window = " << window();
         QQnxBuffer &currentBuffer = m_buffers[m_currentBufferIndex];
 
+#if defined(QQNX_INCREMENTAL_RASTER_UPDATE)
         // Copy unmodified region from old render buffer to new render buffer;
         // required to allow partial updates
         QRegion preserve = m_previousDirty - dirty - m_scrolled;
@@ -72,6 +73,12 @@ void QQnxRasterWindow::post(const QRegion &dirty)
         Q_SCREEN_CHECKERROR(
                 screen_post_window(nativeHandle(), currentBuffer.nativeBuffer(), 1, dirtyRect, 0),
                 "Failed to post window");
+#else
+        // Update the display with contents of render buffer
+        Q_SCREEN_CHECKERROR(
+                screen_post_window(nativeHandle(), currentBuffer.nativeBuffer(), 0, NULL, 0),
+                "Failed to post window");
+#endif
 
         // Advance to next nender buffer
         m_previousBufferIndex = m_currentBufferIndex++;
@@ -79,7 +86,7 @@ void QQnxRasterWindow::post(const QRegion &dirty)
             m_currentBufferIndex = 0;
 
         // Save modified region and clear scrolled region
-        m_previousDirty = dirty;
+        m_previousDirty = QRect(QPoint(0, 0), window()->size());
         m_scrolled = QRegion();
 
         windowPosted();
@@ -149,6 +156,7 @@ int QQnxRasterWindow::pixelFormat() const
 void QQnxRasterWindow::resetBuffers()
 {
     // Buffers were destroyed; reacquire them
+    m_previousBufferIndex = -1;
     m_currentBufferIndex = -1;
     m_previousDirty = QRegion();
     m_scrolled = QRegion();