diff --git a/src/gui/rhi/qrhi.cpp b/src/gui/rhi/qrhi.cpp
index bfcf2d99339..521ea92d942 100644
--- a/src/gui/rhi/qrhi.cpp
+++ b/src/gui/rhi/qrhi.cpp
@@ -4005,11 +4005,11 @@ void QRhiBuffer::endFullDynamicBufferUpdateForCurrentFrame()
 /*!
     \internal
  */
-void QRhiBuffer::fullDynamicBufferUpdateForCurrentFrame(const void *data)
+void QRhiBuffer::fullDynamicBufferUpdateForCurrentFrame(const void *data, quint32 size)
 {
     char *p = beginFullDynamicBufferUpdateForCurrentFrame();
     if (p) {
-        memcpy(p, data, m_size);
+        memcpy(p, data, size > 0 ? size : m_size);
         endFullDynamicBufferUpdateForCurrentFrame();
     }
 }
diff --git a/src/gui/rhi/qrhi.h b/src/gui/rhi/qrhi.h
index 8e5ef695822..ffaa1d88e18 100644
--- a/src/gui/rhi/qrhi.h
+++ b/src/gui/rhi/qrhi.h
@@ -881,7 +881,7 @@ public:
 
     virtual char *beginFullDynamicBufferUpdateForCurrentFrame();
     virtual void endFullDynamicBufferUpdateForCurrentFrame();
-    virtual void fullDynamicBufferUpdateForCurrentFrame(const void *data);
+    virtual void fullDynamicBufferUpdateForCurrentFrame(const void *data, quint32 size = 0);
 
 protected:
     QRhiBuffer(QRhiImplementation *rhi, Type type_, UsageFlags usage_, quint32 size_);
diff --git a/src/gui/rhi/qrhigles2.cpp b/src/gui/rhi/qrhigles2.cpp
index 3954a7d6891..53523ba9143 100644
--- a/src/gui/rhi/qrhigles2.cpp
+++ b/src/gui/rhi/qrhigles2.cpp
@@ -5356,14 +5356,15 @@ void QGles2Buffer::endFullDynamicBufferUpdateForCurrentFrame()
     }
 }
 
-void QGles2Buffer::fullDynamicBufferUpdateForCurrentFrame(const void *bufferData)
+void QGles2Buffer::fullDynamicBufferUpdateForCurrentFrame(const void *bufferData, quint32 size)
 {
+    const quint32 copySize = size > 0 ? size : m_size;
     if (!m_usage.testFlag(UniformBuffer)) {
         QRHI_RES_RHI(QRhiGles2);
         rhiD->f->glBindBuffer(targetForDataOps, buffer);
-        rhiD->f->glBufferSubData(targetForDataOps, 0, m_size, bufferData);
+        rhiD->f->glBufferSubData(targetForDataOps, 0, copySize, bufferData);
     } else {
-        memcpy(data.data(), bufferData, m_size);
+        memcpy(data.data(), bufferData, copySize);
     }
 }
 
diff --git a/src/gui/rhi/qrhigles2_p.h b/src/gui/rhi/qrhigles2_p.h
index 61ab99c260d..a2925eb5c7a 100644
--- a/src/gui/rhi/qrhigles2_p.h
+++ b/src/gui/rhi/qrhigles2_p.h
@@ -38,7 +38,7 @@ struct QGles2Buffer : public QRhiBuffer
     QRhiBuffer::NativeBuffer nativeBuffer() override;
     char *beginFullDynamicBufferUpdateForCurrentFrame() override;
     void endFullDynamicBufferUpdateForCurrentFrame() override;
-    void fullDynamicBufferUpdateForCurrentFrame(const void *data) override;
+    void fullDynamicBufferUpdateForCurrentFrame(const void *data, quint32 size) override;
 
     quint32 nonZeroSize = 0;
     GLuint buffer = 0;