--- /dev/null
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2022 OpenWrt.org
+#
+
+set -ex
+#[ $# -eq 7 ] || {
+[ $# -eq 5 ] || {
+ echo "SYNTAX: $0 <file> <bootfs image> <rootfs image> <bootfs size> <rootfs size>"
+ exit 1
+}
+
+OUTPUT="$1"
+BOOTFS="$2"
+ROOTFS="$3"
+BOOTFSSIZE="$4"
+ROOTFSSIZE="$5"
+#UBOOT="$6"
+#UBOOT_SPL="$7"
+#override UBOOT/UBOOT_SPL with a filler file until u-boot packaging is ready
+UBOOT=`mktemp`
+UBOOT_SPL=`mktemp`
+
+set $(ptgen -o $OUTPUT -v -g -T sifiveu_spl -N loader1 -p 1024 -T sifiveu_uboot -N loader2 -p 4096 -t ef -N boot -p ${BOOTFSSIZE}M -N rootfs -p ${ROOTFSSIZE}M)
+
+ROOTFSOFFSET=$(($7 / 512))
+
+dd bs=512 if="$UBOOT_SPL" of="$OUTPUT" seek=34 conv=notrunc
+dd bs=512 if="$UBOOT" of="$OUTPUT" seek=2082 conv=notrunc
+dd bs=512 if="$BOOTFS" of="$OUTPUT" seek=10274 conv=notrunc
+dd bs=512 if="$ROOTFS" of="$OUTPUT" seek=${ROOTFSOFFSET} conv=notrunc