diff --git a/src/base/ftobjs.c b/src/base/ftobjs.c
index e301f8f11a42af27e55de211e59aeb0f7873a2bb..3cb1d8ecfa405c2950b051ca323e058c5a4b8dd1 100644
--- a/src/base/ftobjs.c
+++ b/src/base/ftobjs.c
@@ -3244,6 +3244,9 @@
     if ( !face )
       return FT_THROW( Invalid_Face_Handle );
 
+    if ( !face->size )
+      return FT_THROW( Invalid_Size_Handle );
+	
     if ( !req || req->width < 0 || req->height < 0 ||
          req->type >= FT_SIZE_REQUEST_TYPE_MAX )
       return FT_THROW( Invalid_Argument );
diff --git a/src/sfnt/sfobjs.c b/src/sfnt/sfobjs.c
index 6edf3ae1ded66380794d1b0cba7fe956ec122e21..ab012827f35a0d8ed6e67825cfb5094eb49ff25d 100644
--- a/src/sfnt/sfobjs.c
+++ b/src/sfnt/sfobjs.c
@@ -528,7 +528,7 @@
     face_index = FT_ABS( face_instance_index ) & 0xFFFF;
 
     /* value -(N+1) requests information on index N */
-    if ( face_instance_index < 0 )
+    if ( face_instance_index < 0 && face_index > 0)
       face_index--;
 
     if ( face_index >= face->ttc_header.count )