Index: usr.sbin/bsdinstall/scripts/zfsboot
===================================================================
--- usr.sbin/bsdinstall/scripts/zfsboot
+++ usr.sbin/bsdinstall/scripts/zfsboot
@@ -659,7 +659,7 @@
 		while :; do
 			# Loop over list of available disks, resetting state
 			for disk in $disks; do
-				f_isset _${disk}_status && _${disk}_status=
+				f_isset _${disk}_status && setvar _${disk}_status
 			done
 
 			# Loop over list of selected disks and create temporary
@@ -667,9 +667,8 @@
 			for disk in $ZFSBOOT_DISKS; do
 				debug= f_device_find -1 \
 					$disk $DEVICE_TYPE_DISK disk
-				f_isset _${disk}_status ||
-					local _${disk}_status
-				_${disk}_status=on
+				local _${disk}_status
+				setvar _${disk}_status on
 			done
 
 			# Create the checklist menu of discovered disk devices