diff --git a/cogl/cogl-buffer-private.h b/cogl/cogl-buffer-private.h
index cf2d9b920..4b21fa388 100644
--- a/cogl/cogl-buffer-private.h
+++ b/cogl/cogl-buffer-private.h
@@ -137,13 +137,17 @@ _cogl_buffer_immutable_ref (CoglBuffer *buffer);
 void
 _cogl_buffer_immutable_unref (CoglBuffer *buffer);
 
-/* This is a wrapper around cogl_buffer_map for internal use when we
-   want to map the buffer for write only to replace the entire
+/* This is a wrapper around cogl_buffer_map_range for internal use
+   when we want to map the buffer for write only to replace the entire
    contents. If the map fails then it will fallback to writing to a
    temporary buffer. When _cogl_buffer_unmap_for_fill_or_fallback is
    called the temporary buffer will be copied into the array. Note
    that these calls share a global array so they can not be nested. */
 void *
+_cogl_buffer_map_range_for_fill_or_fallback (CoglBuffer *buffer,
+                                             size_t offset,
+                                             size_t size);
+void *
 _cogl_buffer_map_for_fill_or_fallback (CoglBuffer *buffer);
 
 void
diff --git a/cogl/cogl-buffer.c b/cogl/cogl-buffer.c
index 7a1a08463..72fd3f852 100644
--- a/cogl/cogl-buffer.c
+++ b/cogl/cogl-buffer.c
@@ -261,6 +261,14 @@ cogl_buffer_unmap (CoglBuffer *buffer)
 
 void *
 _cogl_buffer_map_for_fill_or_fallback (CoglBuffer *buffer)
+{
+  return _cogl_buffer_map_range_for_fill_or_fallback (buffer, 0, buffer->size);
+}
+
+void *
+_cogl_buffer_map_range_for_fill_or_fallback (CoglBuffer *buffer,
+                                             size_t offset,
+                                             size_t size)
 {
   CoglContext *ctx = buffer->context;
   void *ret;
@@ -269,9 +277,11 @@ _cogl_buffer_map_for_fill_or_fallback (CoglBuffer *buffer)
 
   ctx->buffer_map_fallback_in_use = TRUE;
 
-  ret = cogl_buffer_map (buffer,
-                         COGL_BUFFER_ACCESS_WRITE,
-                         COGL_BUFFER_MAP_HINT_DISCARD);
+  ret = cogl_buffer_map_range (buffer,
+                               offset,
+                               size,
+                               COGL_BUFFER_ACCESS_WRITE,
+                               COGL_BUFFER_MAP_HINT_DISCARD);
 
   if (ret)
     return ret;
@@ -281,7 +291,8 @@ _cogl_buffer_map_for_fill_or_fallback (CoglBuffer *buffer)
          the data and then upload it using cogl_buffer_set_data when
          the buffer is unmapped. The temporary buffer is shared to
          avoid reallocating it every time */
-      g_byte_array_set_size (ctx->buffer_map_fallback_array, buffer->size);
+      g_byte_array_set_size (ctx->buffer_map_fallback_array, size);
+      ctx->buffer_map_fallback_offset = offset;
 
       buffer->flags |= COGL_BUFFER_FLAG_MAPPED_FALLBACK;
 
@@ -300,9 +311,10 @@ _cogl_buffer_unmap_for_fill_or_fallback (CoglBuffer *buffer)
 
   if ((buffer->flags & COGL_BUFFER_FLAG_MAPPED_FALLBACK))
     {
-      cogl_buffer_set_data (buffer, 0,
+      cogl_buffer_set_data (buffer,
+                            ctx->buffer_map_fallback_offset,
                             ctx->buffer_map_fallback_array->data,
-                            buffer->size);
+                            ctx->buffer_map_fallback_array->len);
       buffer->flags &= ~COGL_BUFFER_FLAG_MAPPED_FALLBACK;
     }
   else
diff --git a/cogl/cogl-context-private.h b/cogl/cogl-context-private.h
index 7321455d3..788cf3d3c 100644
--- a/cogl/cogl-context-private.h
+++ b/cogl/cogl-context-private.h
@@ -269,6 +269,7 @@ struct _CoglContext
      data */
   GByteArray       *buffer_map_fallback_array;
   CoglBool          buffer_map_fallback_in_use;
+  size_t            buffer_map_fallback_offset;
 
   CoglWinsysRectangleState rectangle_state;
 
diff --git a/cogl/cogl-journal.c b/cogl/cogl-journal.c
index e8eee7906..c762a0b2a 100644
--- a/cogl/cogl-journal.c
+++ b/cogl/cogl-journal.c
@@ -1079,7 +1079,9 @@ upload_vertices (CoglJournal *journal,
   buffer = COGL_BUFFER (attribute_buffer);
   cogl_buffer_set_update_hint (buffer, COGL_BUFFER_UPDATE_HINT_STATIC);
 
-  vout = _cogl_buffer_map_for_fill_or_fallback (buffer);
+  vout = _cogl_buffer_map_range_for_fill_or_fallback (buffer,
+                                                      0, /* offset */
+                                                      needed_vbo_len * 4);
   vin = &g_array_index (vertices, float, 0);
 
   /* Expand the number of vertices from 2 to 4 while uploading */