=== modified file 'initramfs-tools-hook'
--- initramfs-tools-hook	2016-06-21 19:13:11 +0000
+++ initramfs-tools-hook	2017-02-21 21:38:02 +0000
@@ -142,7 +142,7 @@
 for conf in /etc/initramfs-tools/conf.d/*; do
     if [ -n `basename \"$conf\" | grep '^[[:alnum:]][[:alnum:]\._-]*$' \
 	| grep -v '\.dpkg-.*$'` ]; then
-	[ -f ${conf} ] && . ${conf}
+	[ -f "${conf}" ] && . "${conf}"
     fi
 done
 export DEVICE

=== modified file 'initramfs-tools-script'
--- initramfs-tools-script	2016-03-02 16:45:38 +0000
+++ initramfs-tools-script	2017-02-21 21:38:02 +0000
@@ -57,7 +57,7 @@
 # Get DEVICE from /conf/initramfs.conf and other files
 . /conf/initramfs.conf
 for conf in /conf/conf.d/*; do
-    [ -f ${conf} ] && . ${conf}
+    [ -f "${conf}" ] && . "${conf}"
 done
 if [ -e /conf/param.conf ]; then
     . /conf/param.conf