diff --git a/src/hb-unicode.cc b/src/hb-unicode.cc
index 3e8f80764..c5273400f 100644
--- a/src/hb-unicode.cc
+++ b/src/hb-unicode.cc
@@ -269,7 +269,7 @@ hb_unicode_decompose (hb_unicode_funcs_t *ufuncs,
 {
   /* XXX FIXME, move these to complex shapers and propagage to normalizer.*/
   switch (ab) {
-    case 0x0AC9  : *a = 0x0AC5; *b= 0x0ABE; return true;
+    case 0x0AC9  : return false;
 
     case 0x0931  : return false;
     case 0x0B94  : return false;