diff --git a/gfx/d3d/d3d.cpp b/gfx/d3d/d3d.cpp
index 3e98ecccce..112dc5ef06 100644
--- a/gfx/d3d/d3d.cpp
+++ b/gfx/d3d/d3d.cpp
@@ -1032,7 +1032,7 @@ static bool texture_image_render(d3d_video_t *d3d,
    };
 
    /* Load the existing vertices */
-   verts = d3d_vertex_buffer_lock(d3dv, sizeof(newVerts));
+   verts = d3d_vertex_buffer_lock(d3dv);
 
    if (!verts)
       return false;
@@ -1242,7 +1242,7 @@ static void d3d_overlay_render(d3d_video_t *d3d, overlay_t *overlay)
       vert[i][1]  += 0.5f;
    }
 
-   d3d_vertex_buffer_lock(overlay->vert_buf, sizeof(vert));
+   overlay->vert_buf->Lock(0, sizeof(vert), &verts, 0);
    memcpy(verts, vert, sizeof(vert));
    d3d_vertex_buffer_unlock(overlay->vert_buf);
 
diff --git a/gfx/d3d/d3d.h b/gfx/d3d/d3d.h
index 8c375c1713..8736015c61 100644
--- a/gfx/d3d/d3d.h
+++ b/gfx/d3d/d3d.h
@@ -70,7 +70,9 @@ typedef struct
    bool enabled;
    float alpha_mod;
    LPDIRECT3DTEXTURE tex;
+#ifdef HAVE_D3D9
    LPDIRECT3DVERTEXBUFFER vert_buf;
+#endif
 } overlay_t;
 
 #ifdef _XBOX
diff --git a/gfx/d3d/d3d_wrapper.cpp b/gfx/d3d/d3d_wrapper.cpp
index 8c2a1ac3ea..4342a88391 100644
--- a/gfx/d3d/d3d_wrapper.cpp
+++ b/gfx/d3d/d3d_wrapper.cpp
@@ -176,15 +176,16 @@ void d3d_vertex_buffer_unlock(LPDIRECT3DVERTEXBUFFER vertbuf)
 #endif
 }
 
-void *d3d_vertex_buffer_lock(LPDIRECT3DVERTEXBUFFER vertbuf, size_t len)
+void *d3d_vertex_buffer_lock(LPDIRECT3DVERTEXBUFFER vertbuf)
 {
    void *buf;
+
 #if defined(_XBOX1)
    buf = (void*)D3DVertexBuffer_Lock2(vertbuf, 0);
 #elif defined(_XBOX360)
    buf = D3DVertexBuffer_Lock(vertbuf, 0, 0, 0);
 #else
-   vertbuf->Lock(0, len, &buf, 0);
+   vertbuf->Lock(0, sizeof(buf), &buf, 0);
 #endif
 
    if (!buf)
diff --git a/gfx/d3d/d3d_wrapper.h b/gfx/d3d/d3d_wrapper.h
index acac2410d6..db3ef21132 100644
--- a/gfx/d3d/d3d_wrapper.h
+++ b/gfx/d3d/d3d_wrapper.h
@@ -32,7 +32,7 @@ LPDIRECT3DVERTEXBUFFER d3d_vertex_buffer_new(LPDIRECT3DDEVICE dev,
       unsigned length, unsigned usage, unsigned fvf,
       D3DPOOL pool, void *handle);
 
-void *d3d_vertex_buffer_lock(LPDIRECT3DVERTEXBUFFER vertbuf, size_t len);
+void *d3d_vertex_buffer_lock(LPDIRECT3DVERTEXBUFFER vertbuf);
 void d3d_vertex_buffer_unlock(LPDIRECT3DVERTEXBUFFER vertbuf);
 
 void d3d_vertex_buffer_free(void *vertex_data, void *vertex_declaration);
diff --git a/gfx/d3d/render_chain_cg.cpp b/gfx/d3d/render_chain_cg.cpp
index 13a1106c05..7e954e0923 100644
--- a/gfx/d3d/render_chain_cg.cpp
+++ b/gfx/d3d/render_chain_cg.cpp
@@ -1280,7 +1280,7 @@ static void renderchain_set_vertices(
          vert[i].y     += 0.5f;
       }
 
-      verts             = d3d_vertex_buffer_lock(pass->vertex_buf, sizeof(vert));
+      verts             = d3d_vertex_buffer_lock(pass->vertex_buf);
       memcpy(verts, vert, sizeof(vert));
       d3d_vertex_buffer_unlock(pass->vertex_buf);
    }
diff --git a/gfx/d3d/render_chain_xdk.cpp b/gfx/d3d/render_chain_xdk.cpp
index 3ab38c5942..1ff368c933 100644
--- a/gfx/d3d/render_chain_xdk.cpp
+++ b/gfx/d3d/render_chain_xdk.cpp
@@ -202,7 +202,7 @@ static void renderchain_set_vertices(void *data, unsigned pass,
          vert[i].y    += 0.5f / ((float)chain->tex_h);
       }
 
-      verts = d3d_vertex_buffer_lock(chain->vertex_buf, sizeof(vert));
+      verts = d3d_vertex_buffer_lock(chain->vertex_buf);
       memcpy(verts, vert, sizeof(vert));
       d3d_vertex_buffer_unlock(chain->vertex_buf);
    }