--- /usr/share/initramfs-tools/scripts/zfs.orig	2016-04-13 12:43:25.000000000 +0200
+++ /usr/share/initramfs-tools/scripts/zfs	2017-05-06 20:25:50.200005995 +0200
@@ -1,8 +1,24 @@
 # ZFS boot stub for initramfs-tools.
 
+# pseudo-kernel parameter 'zdirs': a comma separated list of device
+# directories to scan on zpool import.
+check_zfs_dev_dirs() {
+	ZDEV_DIRS=
+	for x in $(cat /proc/cmdline); do
+		case $x in
+			zdirs=*) ZDEV_DIRS=",${x#zdirs=}" ;;
+		esac
+	done
+	if [ -n "${ZDEV_DIRS}" ]; then
+		ZDEV_DIRS=$( echo "${ZDEV_DIRS}" | sed -e 's/,/ -d /g' )
+	else
+		ZDEV_DIRS=
+	fi
+}
+
 zfs_test_import()
 {
-	ZFS_STDERR=$(zpool import -o readonly=on -N "$ZFS_RPOOL" 2>&1)
+	ZFS_STDERR=$(zpool import ${ZDEV_DIRS} -o readonly=on -N "$ZFS_RPOOL" 2>&1)
 	ZFS_ERROR=$?
 	if [ "$ZFS_ERROR" -eq 0 ]
 	then
@@ -13,6 +29,7 @@
 
 mountroot()
 {
+	check_zfs_dev_dirs
 	[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/local-top"
 	run_scripts /scripts/local-top
 	[ "$quiet" != "y" ] && log_end_msg
@@ -54,17 +71,17 @@
 
 	# At this point, the pool either imported cleanly, or we ran out of the
 	# allowed time (rootdelay).  Perform the read-write import.
-	ZFS_STDERR=$(zpool import -N "$ZFS_RPOOL" 2>&1)
+	ZFS_STDERR=$(zpool import ${ZDEV_DIRS} -N "$ZFS_RPOOL" 2>&1)
 	ZFS_ERROR=$?
 
 	if [ "$ZFS_ERROR" -ne 0 ]
 	then
-		panic "Command: zpool import -N $ZFS_RPOOL
+		panic "Command: zpool import ${ZDEV_DIRS} -N $ZFS_RPOOL
 Message: $ZFS_STDERR
 Error: $ZFS_ERROR
 
 Manually import the root pool at the command prompt and then exit.
-Hint: Try:  zpool import -f -R / -N $ZFS_RPOOL"
+Hint: Try:  zpool import -f -R / ${ZDEV_DIRS} -N $ZFS_RPOOL"
 	fi
 
 	# Set elevator=noop on the root pool's vdevs' disks.  ZFS already