diff --git a/build/checkstack.pl b/build/checkstack.pl
index 5a8a96d6710da6694eb78ad932ee38b110eb4a94..6bdab11260c1a7dadbd840d5a39358439975bc03 100644
--- a/build/checkstack.pl
+++ b/build/checkstack.pl
@@ -27,7 +27,7 @@
 # use anything else and feel the pain ;)
 {
 	my $arch = shift;
-	$x	= "[0-9a-f]{3,5}";		# hex number     >= 256
+	$x	= "[0-9a-f]{2,5}";		# hex number     >= 256
 	$d	= "([0-9]{2}|[2-9])[0-9]{2}";	# decimal number >= 200
 	if ($arch eq "") {
 		$arch = `uname -m`;