The exact script that does it is in /etc/systemd/nvresizefs.sh on the root partition. It runs resizefs on first boot to extend the / partition to the full extents of the drive. It then self-deletes.
For convenience I am pasting a copy here.
# Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of NVIDIA CORPORATION nor the names of its
# contributors may be used to endorse or promote products derived
# from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
# OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# This is a script to resize partition and filesystem on the root partition
# This will consume all un-allocated sapce on SD card after boot.
set -e
function cleanup()
{
# Delete nvresizefs.sh, nvresizefs.service and its symlink
rm "/etc/systemd/nvresizefs.sh"
rm "/etc/systemd/system/nvresizefs.service"
rm "/etc/systemd/system/multi-user.target.wants/nvresizefs.service"
}
if [ -e "/proc/device-tree/model" ]; then
model="$(tr -d '
Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of NVIDIA CORPORATION nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS’’ AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This is a script to resize partition and filesystem on the root partition
This will consume all un-allocated sapce on SD card after boot.
set -e
function cleanup()
{
# Delete nvresizefs.sh, nvresizefs.service and its symlink
rm “/etc/systemd/nvresizefs.sh”
rm “/etc/systemd/system/nvresizefs.service”
rm “/etc/systemd/system/multi-user.target.wants/nvresizefs.service”
}
if [ -e “/proc/device-tree/model” ]; then
model=“$(tr -d ‘\0’ < /proc/device-tree/model)”
fi
if [ “${model}” != “jetson-nano” ]; then
cleanup
exit 0
fi
Move backup GPT header to end of disk
sgdisk --move-second-header /dev/mmcblk0
Get root partition name i.e partition No. 1
partition_name=“$(sgdisk -i 1 /dev/mmcblk0 |
grep “Partition name” | cut -d' -f2)”
partition_type=“$(sgdisk -i 1 /dev/mmcblk0 |
grep “Partition GUID code:” | cut -d’ ’ -f4)”
partition_uuid=“$(sgdisk -i 1 /dev/mmcblk0 |
grep “Partition unique GUID:” | cut -d’ ’ -f4)”
Get start sector of the root partition
start_sector=“$(cat /sys/block/mmcblk0/mmcblk0p1/start)”
Delete and re-create the root partition
This will resize the root partition.
sgdisk -d 1 -n 1:“${start_sector}”:0 -c 1:“${partition_name}”
-t 1:“${partition_type}” -u 1:“${partition_uuid}” /dev/mmcblk0
Inform kernel and OS about change in partitin table and root
partition size
partprobe /dev/mmcblk0
Resize filesystem on root partition to consume all un-allocated
space on disk
resize2fs /dev/mmcblk0p1
Clean up
cleanup
' < /proc/device-tree/model)"
fi
if [ "${model}" != "jetson-nano" ]; then
cleanup
exit 0
fi
# Move backup GPT header to end of disk
sgdisk --move-second-header /dev/mmcblk0
# Get root partition name i.e partition No. 1
partition_name="$(sgdisk -i 1 /dev/mmcblk0 | \
grep "Partition name" | cut -d -f2)"
partition_type="$(sgdisk -i 1 /dev/mmcblk0 | \
grep "Partition GUID code:" | cut -d' ' -f4)"
partition_uuid="$(sgdisk -i 1 /dev/mmcblk0 | \
grep "Partition unique GUID:" | cut -d' ' -f4)"
# Get start sector of the root partition
start_sector="$(cat /sys/block/mmcblk0/mmcblk0p1/start)"
# Delete and re-create the root partition
# This will resize the root partition.
sgdisk -d 1 -n 1:"${start_sector}":0 -c 1:"${partition_name}" \
-t 1:"${partition_type}" -u 1:"${partition_uuid}" /dev/mmcblk0
# Inform kernel and OS about change in partitin table and root
# partition size
partprobe /dev/mmcblk0
# Resize filesystem on root partition to consume all un-allocated
# space on disk
resize2fs /dev/mmcblk0p1
# Clean up
cleanup
