diff --git a/src/hb-ot-cff1-table.hh b/src/hb-ot-cff1-table.hh
index ddda62a0a..3d658ac62 100644
--- a/src/hb-ot-cff1-table.hh
+++ b/src/hb-ot-cff1-table.hh
@@ -330,7 +330,7 @@ struct Charset0
   {
     mapping->resize (num_glyphs, false);
     for (hb_codepoint_t gid = 1; gid < num_glyphs; gid++)
-      mapping->arrayZ[gid] = {sids[gid - 1], gid + 1};
+      mapping->arrayZ[gid] = {sids[gid - 1], gid};
   }
 
   hb_codepoint_t get_glyph (hb_codepoint_t sid, unsigned int num_glyphs) const
@@ -438,7 +438,7 @@ struct Charset1_2 {
       unsigned count = ranges[i].nLeft + 1;
       unsigned last = gid + count;
       for (unsigned j = 0; j < count; j++)
-	mapping->arrayZ[gid++] = {sid++, last};
+	mapping->arrayZ[gid++] = {sid++, last - 1};
 
       if (gid >= num_glyphs)
         break;
diff --git a/src/hb-subset-cff1.cc b/src/hb-subset-cff1.cc
index 8b5e099f5..835200508 100644
--- a/src/hb-subset-cff1.cc
+++ b/src/hb-subset-cff1.cc
@@ -557,7 +557,7 @@ struct cff1_subset_plan
 
 	if (glyph == old_glyph && skip)
 	{
-	  glyph = hb_min (_.first - 1, glyph_to_sid_map->arrayZ[old_glyph].glyph - 1);
+	  glyph = hb_min (_.first - 1, glyph_to_sid_map->arrayZ[old_glyph].glyph);
 	  sid += glyph - old_glyph;
 	}
       }