diff --git a/util/test/data/GL_Buffer_Updates/backbuffer.png b/util/test/data/GL_Buffer_Updates/backbuffer.png
new file mode 100644
index 000000000..eb21d64ff
Binary files /dev/null and b/util/test/data/GL_Buffer_Updates/backbuffer.png differ
diff --git a/util/test/demos/gl/gl_buffer_updates.cpp b/util/test/demos/gl/gl_buffer_updates.cpp
index 249b7b709..f3a5e1e09 100644
--- a/util/test/demos/gl/gl_buffer_updates.cpp
+++ b/util/test/demos/gl/gl_buffer_updates.cpp
@@ -297,15 +297,19 @@ void main()
 
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(Vec4f),
                                       GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_BUFFER_BIT);
-      memcpy(ptr, &green, sizeof(Vec4f));
+      if(ptr)
+        memcpy(ptr, &green, sizeof(Vec4f));
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[CleanBufferMapWriteNonInvalidate]);
       glBufferData(GL_UNIFORM_BUFFER, sizeof(Vec4f), &red, GL_DYNAMIC_DRAW);
 
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(Vec4f), GL_MAP_WRITE_BIT);
-      ptr->x = 0.0f;
-      ptr->y = 1.0f;
+      if(ptr)
+      {
+        ptr->x = 0.0f;
+        ptr->y = 1.0f;
+      }
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[DirtyBufferMapWriteInvalidate]);
@@ -313,15 +317,19 @@ void main()
 
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(Vec4f),
                                       GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_BUFFER_BIT);
-      memcpy(ptr, &green, sizeof(Vec4f));
+      if(ptr)
+        memcpy(ptr, &green, sizeof(Vec4f));
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[DirtyBufferMapWriteNonInvalidate]);
       glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(Vec4f), &red);
 
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(Vec4f), GL_MAP_WRITE_BIT);
-      ptr->x = 0.0f;
-      ptr->y = 1.0f;
+      if(ptr)
+      {
+        ptr->x = 0.0f;
+        ptr->y = 1.0f;
+      }
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[CleanBufferMapFlushExplicit]);
@@ -329,25 +337,35 @@ void main()
 
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(Vec4f),
                                       GL_MAP_WRITE_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
-      ptr->x = 0.0f;
-      ptr->y = 1.0f;
+      if(ptr)
+      {
+        ptr->x = 0.0f;
+        ptr->y = 1.0f;
+      }
       glFlushMappedBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(float) * 2);
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[DirtyBufferMapFlushExplicit]);
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(Vec4f),
                                       GL_MAP_WRITE_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
-      ptr->x = 0.0f;
-      ptr->y = 1.0f;
+      if(ptr)
+      {
+        ptr->x = 0.0f;
+        ptr->y = 1.0f;
+      }
       glFlushMappedBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(float) * 2);
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
-      memcpy(ptrs[CoherentMapWrite], &red, sizeof(Vec4f));
-      memcpy(ptrs[CoherentMapWriteInvalidateRange], &red, sizeof(Vec4f));
-      memcpy(ptrs[CoherentMapWriteInvalidateBuffer], &red, sizeof(Vec4f));
+      if(ptrs[CoherentMapWrite])
+        memcpy(ptrs[CoherentMapWrite], &red, sizeof(Vec4f));
+      if(ptrs[CoherentMapWriteInvalidateRange])
+        memcpy(ptrs[CoherentMapWriteInvalidateRange], &red, sizeof(Vec4f));
+      if(ptrs[CoherentMapWriteInvalidateBuffer])
+        memcpy(ptrs[CoherentMapWriteInvalidateBuffer], &red, sizeof(Vec4f));
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[NonCoherentMapFlush]);
-      memcpy(ptrs[NonCoherentMapFlush], &red, sizeof(Vec4f));
+      if(ptrs[NonCoherentMapFlush])
+        memcpy(ptrs[NonCoherentMapFlush], &red, sizeof(Vec4f));
       glFlushMappedBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(float) * 4);
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[OffsetMapWrite]);
@@ -355,7 +373,8 @@ void main()
 
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, sizeof(float) * 2, sizeof(float),
                                       GL_MAP_WRITE_BIT);
-      ptr->x = 0.0f;
+      if(ptr)
+        ptr->x = 0.0f;
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
       glBindBuffer(GL_UNIFORM_BUFFER, buffers[OffsetMapFlush]);
@@ -363,7 +382,8 @@ void main()
 
       ptr = (Vec4f *)glMapBufferRange(GL_UNIFORM_BUFFER, sizeof(float) * 2, sizeof(float),
                                       GL_MAP_WRITE_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
-      ptr->x = 0.0f;
+      if(ptr)
+        ptr->x = 0.0f;
       glFlushMappedBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(float));
       glUnmapBuffer(GL_UNIFORM_BUFFER);
 
@@ -382,12 +402,16 @@ void main()
 
           if(buf == CoherentMapWrite || buf == CoherentMapWriteInvalidateRange ||
              buf == CoherentMapWriteInvalidateBuffer)
-            memcpy(ptrs[buf], &green, sizeof(Vec4f));
+          {
+            if(ptrs[buf])
+              memcpy(ptrs[buf], &green, sizeof(Vec4f));
+          }
 
           if(buf == NonCoherentMapFlush)
           {
             glBindBuffer(GL_UNIFORM_BUFFER, buffers[NonCoherentMapFlush]);
-            memcpy(ptrs[NonCoherentMapFlush], &green, sizeof(Vec4f));
+            if(ptrs[NonCoherentMapFlush])
+              memcpy(ptrs[NonCoherentMapFlush], &green, sizeof(Vec4f));
             glFlushMappedBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(float) * 4);
           }
 
diff --git a/util/test/tests/GL/GL_Buffer_Updates.py b/util/test/tests/GL/GL_Buffer_Updates.py
new file mode 100644
index 000000000..3a3f6fe2f
--- /dev/null
+++ b/util/test/tests/GL/GL_Buffer_Updates.py
@@ -0,0 +1,38 @@
+import rdtest
+import renderdoc as rd
+
+
+class GL_Buffer_Updates(rdtest.TestCase):
+    def get_capture(self):
+        return rdtest.run_and_capture("demos_x64", "GL_Buffer_Updates", 5)
+
+    def check_capture(self):
+        self.check_final_backbuffer()
+
+        # Open the capture and grab the thumbnail, check that it is all green too (dirty way of verifying we didn't
+        # break in-app updates but somehow end up with the right data)
+        cap = rd.OpenCaptureFile()
+
+        # Open a particular file
+        status = cap.OpenFile(self.capture_filename, '', None)
+
+        # Make sure the file opened successfully
+        if status != rd.ReplayStatus.Succeeded:
+            cap.Shutdown()
+            raise rdtest.TestFailureException("Couldn't open '{}': {}".format(self.capture_filename, str(status)))
+
+        thumb: rd.Thumbnail = cap.GetThumbnail(rd.FileType.PNG, 0)
+
+        tmp_path = rdtest.get_tmp_path('thumbnail.png')
+
+        with open(tmp_path, 'wb') as f:
+            f.write(thumb.data)
+
+        # The original thumbnail should also be identical, since we have the uncompressed extended thumbnail.
+        ref_path = self.get_ref_path('backbuffer.png')
+
+        if not rdtest.png_compare(tmp_path, ref_path):
+            raise rdtest.TestFailureException("Reference backbuffer and thumbnail image differ", tmp_path, ref_path)
+
+        rdtest.log.success("Thumbnail is identical to reference")
+