diff --git a/debian/changelog b/debian/changelog
index 0d2ea697..1ba7a071 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -6,8 +6,11 @@ livecd-rootfs (2.485) UNRELEASED; urgency=medium
   [ Balint Reczey ]
   * Use default xz compression (-6) for raspi2 image.
     Xz with -0 generated ~35% bigger compressed image. (LP: #1732681)
+  * Zero fill space in UEFI partitions, too
+  * Set LB_ISO_PREPARER to livecd-rootfs to avoid unbound variable in default string
+  * Build minimized images in a 1GiB image
 
- -- Balint Reczey <rbalint@ubuntu.com>  Mon, 20 Nov 2017 21:18:53 +0100
+ -- Balint Reczey <rbalint@ubuntu.com>  Thu, 23 Nov 2017 20:29:29 +0100
 
 livecd-rootfs (2.484) bionic; urgency=medium
 
diff --git a/live-build/auto/config b/live-build/auto/config
index 8c749ec6..4f3304b2 100755
--- a/live-build/auto/config
+++ b/live-build/auto/config
@@ -694,6 +694,7 @@ esac
 lb config noauto \
 	--mode ubuntu \
 	--distribution "$SUITE" \
+	--iso-preparer "livecd-rootfs" \
 	--bootstrap-keyring ubuntu-keyring \
 	--binary-images "$BINARY_IMAGES" \
 	--memtest "$MEMTEST" \
@@ -716,6 +717,11 @@ echo "SUBPROJECT=\"${SUBPROJECT:-}\"" >> config/chroot
 echo "LB_BINARY_HOOKS=\"$BINARY_HOOKS\"" >> config/binary
 echo "BUILDSTAMP=\"$NOW\"" >> config/binary
 echo "SUBPROJECT=\"${SUBPROJECT:-}\"" >> config/binary
+if [ "${SUBPROJECT:-}" = minimized ]; then
+	# try building minimized images in a 1GiB image but still allow overriding
+	# IMAGE_SIZE in lb build
+	echo 'IMAGE_SIZE=${IMAGE_SIZE:-'$((1024*1024*1024))'}' >> config/binary
+fi
 
 case $ARCH+$SUBARCH in
 	armhf+raspi2)
diff --git a/live-build/functions b/live-build/functions
index 549f3be3..04397fdb 100644
--- a/live-build/functions
+++ b/live-build/functions
@@ -171,6 +171,9 @@ umount_disk_image() {
 
     local uefi_dev="/dev/mapper${loop_device///dev/}p15"
     if [ -e "$mountpoint/boot/efi" -a -b "$uefi_dev" ]; then
+	# zero fill free space in UEFI partition
+	cat < /dev/zero > "$mountpoint/boot/efi/bloat_file" 2> /dev/null || true
+	rm "$mountpoint/boot/efi/bloat_file"
         umount --detach-loop "$mountpoint/boot/efi"
     fi
 
diff --git a/live-build/ubuntu-cpc/hooks/032-disk-image.binary b/live-build/ubuntu-cpc/hooks/032-disk-image.binary
index 7989ff6a..71db6d24 100755
--- a/live-build/ubuntu-cpc/hooks/032-disk-image.binary
+++ b/live-build/ubuntu-cpc/hooks/032-disk-image.binary
@@ -3,10 +3,10 @@
 IMAGE_STR="# CLOUD_IMG: This file was created/modified by the Cloud Image build process"
 FS_LABEL="cloudimg-rootfs"
 
-. config/functions
-
 . config/binary
 
+. config/functions
+
 BOOTPART_START=
 BOOTPART_END=
 BOOT_MOUNTPOINT=
diff --git a/live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary b/live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary
index 8e8b0070..1dece0a3 100755
--- a/live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary
+++ b/live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary
@@ -12,6 +12,8 @@ esac
 IMAGE_STR="# CLOUD_IMG: This file was created/modified by the Cloud Image build process"
 FS_LABEL="cloudimg-rootfs"
 
+. config/binary
+
 . config/functions
 
 create_partitions() {
diff --git a/live-build/ubuntu-cpc/hooks/034-disk-image-ppc64el.binary b/live-build/ubuntu-cpc/hooks/034-disk-image-ppc64el.binary
index 649843e4..b97ef55b 100755
--- a/live-build/ubuntu-cpc/hooks/034-disk-image-ppc64el.binary
+++ b/live-build/ubuntu-cpc/hooks/034-disk-image-ppc64el.binary
@@ -10,6 +10,8 @@ esac
 IMAGE_STR="# CLOUD_IMG: This file was created/modified by the Cloud Image build process"
 FS_LABEL="cloudimg-rootfs"
 
+. config/binary
+
 . config/functions
 
 create_partitions() {