diff --git a/release/ia64/doFS.sh b/release/ia64/doFS.sh
index f75b7242315a..054beebd2749 100644
--- a/release/ia64/doFS.sh
+++ b/release/ia64/doFS.sh
@@ -47,6 +47,8 @@ if [ ! -c /dev/${MDDEVICE} ] ; then
     (cd /dev && sh MAKEDEV ${MDDEVICE})
 fi
 
+trap "umount ${MNT}; mdconfig -d -u ${MDDEVICE}" EXIT
+
 EFI_SIZE=$((${FSSIZE}-68))
 
 gpt create ${MDDEVICE}
@@ -68,9 +70,5 @@ df -ki ${MNT}
 
 set `df -ki ${MNT} | tail -1`
 
-umount ${MNT}
-
-mdconfig -d -u ${MDDEVICE} 2>/dev/null || true
-
 echo "*** Filesystem is ${FSSIZE} K, $4 left"
 echo "***     ${FSINODE} bytes/inode, $7 left"
diff --git a/release/scripts/doFS.sh b/release/scripts/doFS.sh
index 8d870fba71ff..08d97a6aa2f6 100644
--- a/release/scripts/doFS.sh
+++ b/release/scripts/doFS.sh
@@ -58,6 +58,9 @@ dofs_vn () {
 	dd of=${FSIMG} if=/dev/zero count=${FSSIZE} bs=1k 2>/dev/null
 
 	vnconfig -s labels -c /dev/r${VNDEVICE} ${FSIMG}
+
+	trap "umount ${MNT}; vnconfig -u /dev/r${VNDEVICE}" EXIT
+
 	disklabel -w ${BOOT} ${VNDEVICE} ${FSLABEL}
 	newfs -i ${FSINODE} -o space -m 0 /dev/r${VNDEVICE}c
 
@@ -73,9 +76,6 @@ dofs_vn () {
 
 	set `df -ki ${MNT} | tail -1`
 
-	umount ${MNT}
-	vnconfig -u /dev/r${VNDEVICE} 2>/dev/null || true
-
 	echo "*** Filesystem is ${FSSIZE} K, $4 left"
 	echo "***     ${FSINODE} bytes/inode, $7 left"
 	break;
@@ -102,6 +102,9 @@ dofs_md () {
 		echo "No /dev/$MDDEVICE" 1>&2
 		exit 1
 	fi
+
+	trap "umount ${MNT}; mdconfig -d -u ${MDDEVICE}" EXIT
+
 	disklabel ${MACHINE} -w ${BOOT} ${MDDEVICE} ${FSLABEL}
 	newfs -i ${FSINODE} -o space -m 0 /dev/${MDDEVICE}c
 
@@ -117,9 +120,6 @@ dofs_md () {
 
 	set `df -ki ${MNT} | tail -1`
 
-	umount ${MNT}
-	mdconfig -d -u ${MDDEVICE} 2>/dev/null || true
-
 	echo "*** Filesystem is ${FSSIZE} K, $4 left"
 	echo "***     ${FSINODE} bytes/inode, $7 left"
 	break;