--- a/gfx/harfbuzz/src/hb-ot-shape-complex-sea.cc
+++ b/gfx/harfbuzz/src/hb-ot-shape-complex-sea.cc
@@ -176,18 +176,18 @@ set_sea_properties (hb_glyph_info_t &inf
 
   info.sea_category() = (sea_category_t) cat;
   info.sea_position() = pos;
 }
 
 
 static void
 setup_masks_sea (const hb_ot_shape_plan_t *plan HB_UNUSED,
-		   hb_buffer_t              *buffer,
-		   hb_font_t                *font HB_UNUSED)
+		 hb_buffer_t              *buffer,
+		 hb_font_t                *font HB_UNUSED)
 {
   HB_BUFFER_ALLOCATE_VAR (buffer, sea_category);
   HB_BUFFER_ALLOCATE_VAR (buffer, sea_position);
 
   /* We cannot setup masks here.  We save information about characters
    * and setup masks later on in a pause-callback. */
 
   unsigned int count = buffer->len;
@@ -233,18 +233,19 @@ initial_reordering_consonant_syllable (c
   }
   for (; i < end; i++)
   {
     if (info[i].sea_category() == OT_MR) /* Pre-base reordering */
     {
       info[i].sea_position() = POS_PRE_C;
       continue;
     }
-    if (info[i].sea_position() < POS_BASE_C) /* Left matra */
+    if (info[i].sea_category() == OT_VPre) /* Left matra */
     {
+      info[i].sea_position() = POS_PRE_M;
       continue;
     }
 
     info[i].sea_position() = POS_AFTER_MAIN;
   }
 
   buffer->merge_clusters (start, end);
   /* Sit tight, rock 'n roll! */
@@ -258,19 +259,19 @@ initial_reordering_broken_cluster (const
 				   unsigned int start, unsigned int end)
 {
   /* We already inserted dotted-circles, so just call the consonant_syllable. */
   initial_reordering_consonant_syllable (plan, face, buffer, start, end);
 }
 
 static void
 initial_reordering_non_sea_cluster (const hb_ot_shape_plan_t *plan HB_UNUSED,
-					hb_face_t *face HB_UNUSED,
-					hb_buffer_t *buffer HB_UNUSED,
-					unsigned int start HB_UNUSED, unsigned int end HB_UNUSED)
+				    hb_face_t *face HB_UNUSED,
+				    hb_buffer_t *buffer HB_UNUSED,
+				    unsigned int start HB_UNUSED, unsigned int end HB_UNUSED)
 {
   /* Nothing to do right now.  If we ever switch to using the output
    * buffer in the reordering process, we'd need to next_glyph() here. */
 }
 
 
 static void
 initial_reordering_syllable (const hb_ot_shape_plan_t *plan,