diff --git a/distrib/miniroot/install.sub b/distrib/miniroot/install.sub
index 2b6518902fed..0a299f74bf96 100644
--- a/distrib/miniroot/install.sub
+++ b/distrib/miniroot/install.sub
@@ -1,5 +1,5 @@
 #!/bin/sh
-#	$NetBSD: install.sub,v 1.52 2020/01/19 00:50:25 kre Exp $
+#	$NetBSD: install.sub,v 1.53 2020/01/19 00:57:00 kre Exp $
 #
 # Copyright (c) 1996 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -523,7 +523,7 @@ if [ -f /mnt/etc/rc.conf ]; then
 		echo -n "configuring network interfaces:"
 		for i in $tmp; do
 			eval $(echo 'args=$ifconfig_'$i)
-			if [ ! -z "$args" ]; then
+			if [ -n "$args" ]; then
 				echo -n " $i"
 				ifconfig $i $args
 			elif [ -f /mnt/etc/ifconfig.$i ]; then
@@ -555,7 +555,7 @@ else
 			read af name mask bcaddr extras
 			read dt dtaddr
 
-			if [ ! -n "$name" ]; then
+			if [ -z "$name" ]; then
 		    echo "/etc/hostname.$1: invalid network configuration file"
 				exit
 			fi
@@ -1047,7 +1047,7 @@ The following filesystem types are supported:
 __mount_a_disk_2
 	_md_fstype=$(md_native_fstype)
 	_md_fsopts=$(md_native_fsopts)
-	if [ ! -z "$_md_fstype" ]; then
+	if [ -n "$_md_fstype" ]; then
 		echo "	3) $_md_fstype"
 	else
 		_md_fstype="_undefined_"