diff --git a/fab/gmerge b/fab/gmerge
index b80aca2..9fafbe3 100755
--- a/fab/gmerge
+++ b/fab/gmerge
@@ -2,8 +2,8 @@
 #
 # gmerge - Merge multiple KiCAD Gerber files into one
 #
-# Written 2011 by Werner Almesberger
-# Copyright 2011 Werner Almesberger
+# Written 2011, 2016 by Werner Almesberger
+# Copyright 2011, 2016 Werner Almesberger
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -29,7 +29,8 @@ LINE: while (<>) {
 			$state = "CMD";
 			next;
 		}
-		die "unrecognized aperture" unless /^%ADD(\d+)C,((\d|\.)+)\*%/;
+		die "unrecognized aperture"
+		    unless /^%ADD(\d+)([CRO],(\d|\.)+(X(\d|\.)+)?)\*%/;
 		for (keys %apt) {
 			if ($apt{$_} == $2) {
 				$map{$1} = $_;
@@ -71,7 +72,7 @@ LINE: while (<>) {
 print $ghdr || die $!;
 print "G04 APERTURE LIST*\n" || die $!;
 for (sort keys %apt) {
-	print "\%ADD".$_."C,".$apt{$_}."*%\n" || die $!;
+	print "\%ADD".$_.$apt{$_}."*%\n" || die $!;
 }
 print "G04 APERTURE END LIST*\n" || die $!;
 print $c || die $!;