Import patches-unapplied version 2.509 to ubuntu/bionic-proposed

Imported using git-ubuntu import.

Changelog parent: 54408aa50613316ff7698fbfcdc86ed23317ca47

New changelog entries:
  [ Steve Langasek ]
  * Properly handle loop device names when there are > 10 devices on the
    system.
  [ Dimitri John Ledkov ]
  * Build EFI armhf images.

debian/changelog

@@ -1,3 +1,14 @@
+livecd-rootfs (2.509) bionic; urgency=medium
+
+  [ Steve Langasek ]
+  * Properly handle loop device names when there are > 10 devices on the
+    system.
+
+  [ Dimitri John Ledkov ]
+  * Build EFI armhf images.
+
+ -- Dimitri John Ledkov <xnox@ubuntu.com>  Tue, 06 Mar 2018 12:58:46 +0000
+
 livecd-rootfs (2.508) bionic; urgency=medium
 
   * Use Ubuntu-specific branches when seeding snaps, as required in

live-build/functions

@@ -56,7 +56,7 @@ mount_image() {
 
     # Find the loop device
     loop_p1="$(echo -e ${kpartx_mapping} | head -n1 | awk '{print$3}')"
-    loop_device="/dev/loop$(echo ${loop_p1} | cut -b5)"
+    loop_device="/dev/${loop_p1%p[0-9]*}"
     if [ ! -b ${loop_device} ]; then
         echo "unable to find loop device for ${backing_img}"
         exit 1

live-build/ubuntu-cpc/hooks/032-disk-image.binary

@@ -17,7 +17,7 @@ case $ARCH:$SUBARCH in
 		echo "POWER disk images are handled separately"
 		exit 0
 		;;
-	amd64|arm64)
+	amd64|arm64|armhf)
 		echo "We only create EFI images for $ARCH."
 		exit 0
 		;;

live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary

@@ -1,7 +1,7 @@
 #!/bin/bash -eux
 
 case $ARCH in
-    amd64|arm64)
+    amd64|arm64|armhf)
         ;;
     *)
         echo "We don't create EFI images for $ARCH."
@@ -20,7 +20,7 @@ create_partitions() {
     disk_image="$1"
     sgdisk "${disk_image}" --zap-all
     case $ARCH in
-        arm64)
+        arm64|armhf)
             sgdisk "${disk_image}" \
                 --new=15:0:204800 \
                 --typecode=15:ef00 \
@@ -83,6 +83,10 @@ install_grub() {
             chroot mountpoint apt-get -qqy install --no-install-recommends grub-efi-arm64 grub-efi-arm64-bin
             efi_target=arm64-efi
             ;;
+        armhf)
+            chroot mountpoint apt-get -qqy install --no-install-recommends grub-efi-arm grub-efi-arm-bin
+            efi_target=arm-efi
+            ;;
         amd64)
             chroot mountpoint apt-get install -qqy grub-efi-amd64-signed grub-efi-amd64 shim-signed
             efi_target=x86_64-efi