Index: head/release/arm64/mkisoimages.sh
===================================================================
--- head/release/arm64/mkisoimages.sh
+++ head/release/arm64/mkisoimages.sh
@@ -0,0 +1,93 @@
+#!/bin/sh
+#
+# $FreeBSD$
+#
+# This script is used by release/Makefile to build the (optional) ISO images
+# for a FreeBSD release.  It is considered architecture dependent since each
+# platform has a slightly unique way of making bootable CDs. This script is
+# also allowed to generate any number of images since that is more of
+# publishing decision than anything else.
+#
+# Usage:
+#
+# mkisoimages.sh [-b] image-label image-name base-bits-dir [extra-bits-dir]
+#
+# Where -b is passed if the ISO image should be made "bootable" by
+# whatever standards this architecture supports (may be unsupported),
+# image-label is the ISO image label, image-name is the filename of the
+# resulting ISO image, base-bits-dir contains the image contents and
+# extra-bits-dir, if provided, contains additional files to be merged
+# into base-bits-dir as part of making the image.
+
+set -e
+
+scriptdir=$(dirname $(realpath $0))
+. ${scriptdir}/../../tools/boot/install-boot.sh
+
+if [ -z $ETDUMP ]; then
+	ETDUMP=etdump
+fi
+
+if [ -z $MAKEFS ]; then
+	MAKEFS=makefs
+fi
+
+if [ -z $MKIMG ]; then
+	MKIMG=mkimg
+fi
+
+if [ "$1" = "-b" ]; then
+	BASEBITSDIR="$4"
+
+	# Make an EFI system partition.
+	# The ISO file is a special case, in that it only has a maximum of
+	# 800 KB available for the boot code. So make an 800 KB ESP
+	espfilename=$(mktemp /tmp/efiboot.XXXXXX)
+	make_esp_file ${espfilename} 800 ${BASEBITSDIR}/boot/loader.efi
+
+	bootable="-o bootimage=efi;${espfilename} -o no-emul-boot -o platformid=efi"
+
+	shift
+else
+	BASEBITSDIR="$3"
+	bootable=""
+fi
+
+if [ $# -lt 3 ]; then
+	echo "Usage: $0 [-b] image-label image-name base-bits-dir [extra-bits-dir]"
+	exit 1
+fi
+
+LABEL=`echo "$1" | tr '[:lower:]' '[:upper:]'`; shift
+NAME="$1"; shift
+
+publisher="The FreeBSD Project.  https://www.FreeBSD.org/"
+echo "/dev/iso9660/$LABEL / cd9660 ro 0 0" > "$BASEBITSDIR/etc/fstab"
+$MAKEFS -t cd9660 $bootable -o rockridge -o label="$LABEL" -o publisher="$publisher" "$NAME" "$@"
+rm -f "$BASEBITSDIR/etc/fstab"
+rm -f ${espfilename}
+
+if [ "$bootable" != "" ]; then
+	# Look for the EFI System Partition image we dropped in the ISO image.
+	for entry in `$ETDUMP --format shell $NAME`; do
+		eval $entry
+		# XXX: etdump(8) returns "default" for the initial entry
+		if [ "$et_platform" = "default" ]; then
+			espstart=`expr $et_lba \* 2048`
+			espsize=`expr $et_sectors \* 512`
+			espparam="-p efi::$espsize:$espstart"
+			break
+		fi
+	done
+
+	# Create a GPT image containing the EFI partition.
+	imgsize=`stat -f %z "$NAME"`
+	$MKIMG -s gpt \
+	    --capacity $imgsize \
+	    $espparam \
+	    -o efi.img
+
+	# Drop the GPT into the System Area of the ISO.
+	dd if=efi.img of="$NAME" bs=32k count=1 conv=notrunc
+	rm -f efi.img
+fi