Flashing Support¶

Use flash.sh to flash a Jetson device with Bootloader and the kernel, and optionally, flash the root file system to an internal or external storage device.

Use l4t_initrd_flash.sh to flash internal or external media connected to a Jetson device. This script uses the recovery initial ramdisk to do the flashing, and can flash internal and external media using the same procedure. Because this script uses the kernel for flashing, it is generally faster than flash.sh. See Flashing with Initrd for more details.

Before You Begin¶

The following directories must be present:

bootloader: Bootloader plus flashing tools, such as TegraFlash, CFG, and BCT
kernel: A kernel image /Image, DTB files, and kernel modules
rootfs: The root file system that you downloaded

This directory starts empty. You populate it with the sample file system.
nv_tegra: User space binaries and sample applications

Additionally, before running these commands, you must connect your host computer to the Jetson device’s recovery port with a USB cable.

Basic Flashing Script Usage¶

Display the current usage information for flash.sh by running flash.sh –h, using the script included in the release. The basic usage is:

$ sudo ./flash.sh [options] <board> <rootdev>

Where:

options is one or more command line options. All of the options are optional. See Flashing Script Usage for information about the options.
<board> specifies the configuration to be applied to the device to be flashed. Values are listed in the table in Jetson Modules and Configurations in the topic Quick Start. flash.sh gets the configuration from a configuration file named <board>.conf.
<rootdev> specifies the type of device to be flashed. Use the value mmcblk0p1 to flash a local storage device (eMMC or SD card, depending on platform), as distinguished from an NFS server, for example.

Basic Flashing Procedures¶

This section describes some common procedures for flashing one or more target devices.

To flash the target device¶

Put the target device into Force Recovery Mode.
1. Power on the carrier board and hold down the RECOVERY button.
2. Press the RESET button.
Run the flash.sh script that is in the top-level directory of BSP for this release. The command line must specify the target board (e.g. jetson-agx-xavier-devkit) for the root file system:
```
$ sudo ./flash.sh <board> <rootdev>
```
Where:
- <board> specifies the configuration of the target device, as described by the table in Jetson Modules and Configurations in the topic Quick Start.
- <rootdev> specifies the device on which the root file system is located, as described in Basic Flashing Script Usage.

For examples, run the script like this:

$ sudo ./flash.sh <board> mmcblk0p1

To flash using a convenient script¶

NVIDIA provides a convenient flashing script which automatically detects the Jetson device’s type of carrier board:

$ sudo ./nvsdkmanager_flash.sh [--storage <storage> ]

Where --storage is supported on Jetson Xavier NX series and Jetson AGX Xavier series only. It can be nvme0n1p1 for flashing to an external NVMe SSD, or sda1 for flashing to an external USB storage drive.

On Jetson Xavier NX series, flashing with the --storage option flashes only QSPI and external NVMe or USB storage; it does not flash the internal eMMC/SD storage.

To flash the target device to mount a rootfs specified by UUID¶

For an internal storage device (e.g. eMMC or an SD card), enter the command:
```
$ sudo ./flash.sh <board> internal
```
This command stores the UUID used for the root file system partition in the file bootloader/l4t-rootfs-uuid.txt. You may specify your own UUID by writing the UUID to this file before executing the command above.
For an external stage device (e.g. an NVMe or USB device), enter the command:
```
$ sudo ./flash.sh <board> external
```
This command stores the UUID used for the root file system partition in the file bootloader/l4t-rootfs-uuid.txt_ext. You may specify your own UUID by writing the UUID to this file before executing the command above.

To flash the target device to mount a rootfs specified by partition device name¶

For a partition on a USB storage device connected to the Jetson device, enter this command:
```
$ sudo ./flash.sh <board> sda<x>
```
For a partition on an NVMe storage device connected to the Jetson device, enter this command:
```
$ sudo ./flash.sh <board> nvme0n1p<x>
```
Where:
- <board> specifies the configuration of the target device, as described in the table of device names in the topic Quick Start.
- <x> is a number specifying the APP partition’s position on the storage device, e.g. sda1 for a USB device, or nvme0n1p1 for an NVMe storage device.

To clone a Jetson device and flash¶

Copy system.img from the file system partition you want to flash from. Enter the command:
```
$ sudo ./flash.sh -r -k APP -G <clone> <board> mmcblk0p1
```
Where:
- <clone> determines the names of the copies.
- <board> specifies the configuration of the target device.
This step creates two copies of <clone> in the <top> directory: a sparsed image (smaller than the original) named <clone>, and an exact copy named <clone>.raw.

For example, if <clone> is original.img, flash.sh creates a sparsed image named original.img and an exact copy named original.img.raw.
Copy <clone>.img to the <BSP>/bootloader/system.img directory, where <BSP> is the directory in which the Jetson Linux BSP is installed. Enter the command:
```
$ sudo cp <clone>.img bootloader/system.img
```
Flash the image to the target board.
- If the target board has already been flashed, reflash the clone image to the APP partition. Enter the command:
```
$ sudo ./flash.sh -r -k APP <board> mmcblk0p1
```
- If the target board has never been flashed, flash all of the board’s partitions. Enter the command:
  
  $ sudo ./flash.sh -r <board> mmcblk0p1

To back up and restore a Jetson device¶

NVIDIA provides tools for creating a backup image of a Jetson device and restoring the Jetson from a backup image.

Backing up a Jetson device differs from cloning one (see To clone a Jetson device and flash) because a backup image includes every partition in the device’s internal eMMC and QSPI memory, while a clone contains only the APP file system partition.

The tools for backing up and restoring a Jetson device are in this directory in the BSD:

/Linux_for_Tegra/tools/backup-restore/

Instructions for backing up and restoring a device are in the file README_backup_restore.txt in the same directory.

To RCM boot to NFS¶

Note

To create a bootable NFS root file system, you must first:

Perform the process described in Step 1: Set Up the Root File System <https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/rootfs_custom.html#wwpID0E0JG0HA>
Perform the process described in Configuring NFS Root on the Linux Host <https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/getting_started.html#wwpID0E0CC0HA>

Put the device into reset/recovery mode.
- Power on the carrier board and hold down the RECOVERY button.
- Press the RESET button.
Enter the command:
```
$ sudo./flash.sh -N <ip_addr>:<root_path> --rcm-boot <board> eth0
```
Where:
- <ip_addr> is the IP address of the host system
- <root_path> is the path to the NFS rootfs
- <board> is the configuration of the target device as specified by the table in Jetson Modules and Configurations in the topic Quick Start

Flashing Script Usage¶

This section complements Basic Flashing Script Usage by providing detailed information about flash.sh command line options and other aspects of flash.sh usage.

Command line option	Description
-b <bctfile>	Deprecated. Pathname of a boot control table configuration file.
-c <cfgfile>	Pathname of a flash partition table configuration file.
-d <dtbfile>	Pathname of a device tree file.
-e <emmc_size>	Deprecated. Target device’s eMMC memory size. Applies only to target devices that use eMMC.
-f <flashapp>	Name of the flash application to be used. Flash applications are stored in the bootloader directory. The default flash application is `bootloader/tegraflash.py`.
-h	Prints descriptions of the command line syntax and command line options.
-k <partition_id>	Partition name or number specified in `flash.xml` or `flash.cfg`.
-m <mts_preboot>	Name of the MTS preboot file to be used, such as `mts_preboot`.
-n <nfs_args>	Static NFS network assignments: `<Client_IP>:<Server_IP>:<Gateway_IP>:<Netmask>`.
-o <odmdata>	ODM data.
-p <bp_size>	Total eMMC hardware boot partition size.
-r	Skips building `system.img`; reuse the existing one.
-s <PKC_key_file>	Deprecated. Pathname of a file containing the PKC key used for signing and building `bl_update_payload`.
-t <tegraboot>	Pathname of a tegraboot binary, such as `nvtboot.bin`.
-u <PKC_key_file>	Pathname of a file containing the PKC key used for an ODM fused board.
-v <SBK_key_file>	Pathname of a file containing the Secure Boot Key (SBK) used for an ODM fused board.
-w <wb0boot>	Pathname of a warm boot binary, such as `nvtbootwb0.bin`.
-x <tegraid>	Processor chip ID. The default value is: NVIDIA^® Jetson AGX Orin™: 0x23 NVIDIA^® Jetson Xavier™ NX series and NVIDIA^® Jetson AGX Xavier™ series: 0x19
-z <sn>	Serial number of the target board.
-B <boardid>	Board ID.
-C <args>	Kernel command line arguments. If this option is specified, it overrides the default values defined for `flash.sh`. If two or more arguments are specified, they must be enclosed in quotation marks and separated by spaces. Kernel command line arguments are documented in the file `kernel-4.9/Documentation/kernel-parameters.txt`. In the case of NFS booting, use this option to set NFS boot-related arguments if the `-I` option is omitted.
-F <flasher>	Pathname of a flash server, such as `nvtboot_recovery_cpu.bin`.
-G <file_name>	Reads the boot partition and saves the image to the specified file.
-I <initrd>	Pathname of the initrd file. The default value is null.
-K <kernel>	Pathname of a kernel image file such as `zImage` or `Image`.
-L <bootloader>	Pathname of a boot loader, such as `nvtboot_t194.bin`.
-M <mts boot>	Pathname of an MTS boot file, such as `mts_si`.
-N <nfsroot>	NFS root address, such as `<my_IP_address>:/my/exported/nfs/rootfs`.
-P <ppt_end_plus1>	Deprecated. End of the PPT plus 1; primary GPT start address + size of PPT + 1.
-R <rootfs_dir>	Pathname of the sample rootfs directory.
-S <size>	Size of the rootfs in bytes. Valid only for an internal root device. KB/MB/GB suffixes represent units of 1000, 1000², and 1000³. The suffixes `KiB`/`MiB`/`GiB` represent of multipliers of 1024, 1024², and 1024³. For example, `2GiB` represents 2×1024³ bytes.
–bup	Generates Bootloader update payload (BUP).
–clean-up	Cleans up the BUP buffer when the script is flashing a multi-spec BUP.
–multi-spec	Enables support for building a multi-spec BUP.
–no-flash	Performs all steps except physically flashing the board. The script creates a `system.img` file.
–no-systemimg	Prevents creation or re-creation of `system.img`.
–sparseupdate	Only flash partitions that have changed. Currently supports only SPI flash memory.
–usb-instance <id>	USB instance to connect to; `<id>` is an integer ID (e.g. 0, 1), a bus/dev specification (e.g. 003/091), or a USB port path (e.g. 3-14). The last is the recommended form.
–user_key <user_key_file>	Pathname of a file containing a user key which may be used to encrypt and decrypt kernel, kernel-dtb, and initrd binary images. If `user_key` is specified, then the `-v` option must also be specified.
–sparseupdate	only flash partitions that have changed. Currently only support SPI flash memory

Flashing to a USB Drive¶

Jetson devices can be booted from a mass storage class USB device with bulk-only protocol, such as a flash drive. Hot plugging is not supported; the flash drive must be attached before the Jetson device is booted. You can manually set up a flash drive for booting as explained in To set up a flash drive manually for booting.

All Jetson devices can boot from internal storage using a boot partition and can mount an external USB drive as the root file system.

NVIDIA provides a way to simplify flashing to a USB drive that is connected to a Jetson device. For details, see To set up a USB drive for booting using flash with initrd.

Note

Jetson AGX Xavier series devices use boot firmware that is stored only on internal eMMC memory. Consequently this type of device cannot boot from USB or NVMe SSD until its internal eMMC has been flashed.

To set up a flash drive manually for booting¶

For this method only, confirm that the device can boot successfully from eMMC. If it cannot, correct the problem by flashing to eMMC first.
Connect the flash drive to the host computer.
Check the flash drive’s device name (e.g. /dev/sdb):
```
$ sudo lsblk -p -d | grep sd
```
Create a new GPT:
```
$ sudo parted /dev/<sdx> mklabel gpt
```
Where <sdx> is the device name that your host computer assigned to the flash drive.

For example, if the host computer assigns the flash drive device name sdb, the command is:
```
$ sudo parted /dev/sdb mklabel gpt
```
Add the APP partition:
```
$ sudo parted /dev/<sdx> mkpart APP 0GB <size>
```
Where <size> is the size of the partition. It must be at least 16 GB. It may be larger if the flash drive has enough space.

For example, if <sdx> is sdb and the partition is to contain 16 GB, enter:
```
$ sudo parted /dev/sdb mkpart APP 0GB 16GB
```
The device name of the APP partition is /dev/<sdx>1.
Format APP as an ext4 partition, and mount it:
```
$ sudo mkfs.ext4 /dev/<sdx>1
$ sudo mount /dev/<sdx>1 /mnt
```
You may format APP as ext2 or ext3, but ext4 is strongly recommended because it is faster, more compact, and more reliable.
Connect the Jetson device to a host computer and put it into recovery mode, then enter these commands to generate the rootfs without flashing the device:
```
$ cd Linux_for_Tegra/
$ sudo BOOTDEV=sda1 ./flash.sh --no-flash <board> <sdxn>
$ sudo mkdir tmp_system
$ sudo mount bootloader/system.img.raw ./tmp_system
$ sudo rsync -axHAWX --numeric-ids --info=progress2 --exclude=/proc ./tmp_system/ /mnt
```
Where:
- <board> is the type of Jetson device to be flashed. See the table in Jetson Modules and Configurations in the topic Quick Start.
- <sdxn> is the device name that the Jetson device assigns to APP (e.g. sda1).
Unmount the flash drive and disconnect it from the host computer:
```
$ sudo umount /mnt
$ sudo umount ./tmp_system
```
Plug the flash drive into the target device and power it on or reboot it.
If your device still boots from its internal storage, you may need to modify the UEFI source code to change the boot-order.

To set up a flash drive manually for using as root file system¶

Prepare the flash drive similarly to

To set up a flash drive manually for booting.

Flash the Jetson device to mount the external flash drive:
```
$ sudo ./flash.sh <board> sda1
```

To prepare files to boot from a flash drive with Secure Boot¶

When the Secureboot package is installed, the kernel file /boot/Image must be signed, and the signature file must be saved as /boot/Image.sig.

If you use flash.sh to flash a device with Secure Boot installed, the script automatically creates and stores the signature file. If you create a signature file manually, you must also save it manually. For more information, see the topic Secure Boot.

To set up a USB drive as a boot device or root file system using flash with initrd¶

By flashing with initrd you can flash to an external USB device attached to a Jetson device. For more information, see Flashing to an External Storage Device.

Flashing to an NVMe Drive¶

Jetson devices can be booted from an NVMe drive. Hot-plugging is not supported; the NVMe drive must be attached before the Jetson device is booted.

You can manually set up an NVMe drive for booting by following the steps in To set up an NVMe drive manually for booting.

All Jetson devices can boot from internal storage using a boot partition and mount an external NVMe drive as the root file system.

NVIDIA provides a way to simplify flashing to an NVMe drive that is connected to a Jetson device. For details, see To set up an NVMe drive for booting using flash with initrd.

Note

Jetson AGX Xavier series devices use boot firmware that is stored only on internal eMMC memory. Consequently this type of device can boot from USB or NVMe drive only after its internal eMMC has been flashed.

To set up an NVMe drive manually for booting¶

Confirm that the device can boot successfully from eMMC. If it cannot, correct the problem by flashing to eMMC first.
Connect the NVMe drive to the host computer.
Check the NVMe drive’s device name (e.g. /dev/nvme0n1):
```
$ lsblk -d -p | grep nvme | cut -d\  -f 1
```
Note that there must be two spaces after the -d\.
Create a new GPT:
```
$ sudo parted /dev/<nvmeXn1> mklabel gpt
```
Where <nvmeXn1> is the device name that your host computer assigns to the NVMe drive.

For example, if the host computer assigns the NVMe drive device name nvme0n1, the command is:
```
$ sudo parted /dev/nvme0n1 mklabel gpt
```
Add the APP partition:
```
$ sudo parted /dev/<nvmeXn1> mkpart APP 0GB <size>
```
Where <size> is the size of the partition. It must be at least 16 GB. It may be larger if the NVMe drive has enough space.

For example, if <nvmeXn1> is nvme0n1 and the partition is to contain 16 GB, enter:
```
$ sudo parted /dev/nvme0n1 mkpart APP 0GB 16GB
```
The device name of the APP partition is then /dev/<nvmeXn1>p1.
Format APP as an ext4 partition, and mount it:
```
$ sudo mkfs.ext4 /dev/<nvmeXn1>p1
$ sudo mount /dev/<nvmeXn1>p1 /mnt
```
You may format APP as ext2 or ext3, but ext4 is strongly recommended because it is faster, more compact, and more reliable.

Connect the Jetson device to a host computer and put it into recovery mode, then enter the following commands to generate the rootfs without flashing the device:

$ cd Linux_for_Tegra/
$ sudo BOOTDEV=nvme0n1p1 ./flash.sh --no-flash <board> nvme0n1p1
$ sudo mkdir tmp_system
$ sudo mount bootloader/system.img.raw ./tmp_system
$ sudo rsync -axHAWX --numeric-ids --info=progress2 --exclude=/proc ./tmp_system/ /mnt

Where nvme0n1p1 is the device name that the Jetson device will assign to APP.

Unmount the NVMe drive and disconnect it from the host computer:
```
$ sudo umount /mnt
$ sudo umount ./tmp_system
```
Plug the NVMe drive into the Jetson device and power on.
Set the Jetson device to boot from the NVMe drive in the U-Boot environment:

To test directly, enter run bootcmd_nvme0 at the U-Boot prompt.
To set NVMe to boot first with a plain boot command, change the U-Boot variable boot_targets to "nvme0 mmc1 mmc0 usb0 pxe dhcp", then enter the U-Boot command run boot.
To make the change permanent, run saveenv in U-Boot after changing boot_targets but before booting.

To set up an NVMe drive manually for using as root file system¶

Prepare the NVMe device similarly to

To set up a NVMe drive manually for booting.

Flash your Jetson to mount the external NVMe drive:
```
$ sudo ./flash.sh <board> nvme0n1p1
```

To prepare files to boot from an NVMe drive with Secure Boot¶

See To prepare files to boot from a flash drive with Secure Boot.

To set up an NVMe drive as a boot device or root file system using flash with initrd¶

By flashing with initrd you can flash to an external NVMe SSD attached to a Jetson device. For more information, see Flashing to an External Storage Device.

Flashing to an SD Card¶

Applies to: Jetson Xavier NX development module only

This section describes procedures for flashing and utilizing an SD card for a Jetson Xavier NX series module (P3668-0000 or P3668-0003). P3668-0000 is used only as a component of Jetson Xavier NX Developer Kit.

Prerequisites¶

Download Etcher for Linux. Etcher is the tool you use to copy an image to an SD card. It is available from the Balena Etcher home page.

Download Etcher for Linux x64 (64-bit) (AppImage). Make the downloaded file executable.

Note

NVIDIA recommends using Etcher to copy an image to an SD card because it is an easy and foolproof method. If you prefer, you can perform this operation with the Linux dd command. If you use this method, you need not download Etcher.

To generate an image to be flashed to an SD card¶

Applies to: Jetson Xavier NX series only

If you have not already done so, expand the archive linux_for_tegra.tbz2.
Go to the directory Linux_for_Tegra/tools.
Enter the command:
```
$ ./jetson-disk-image-creator.sh -o <blob_name> -b <board>
```
Where:
- <blob_name> is a filename; the script saves the raw image with this name.
- <board> specifies the type of Jetson device that the SD card is to be flashed for. You can find the appropriate value of <board> in the table in Jetson Modules and Configurations in the topic Quick Start.
This command generates a raw image with partitions per the SPI-SD profile for a Jetson Xavier NX development module.

For example, to create a raw image file named sd-blob.img for use on a Jetson Xavier NX development module:
```
$ ./jetson-disk-image-creator.sh -o sd-blob.img -b jetson-xavier-nx-devkit -r 100
```

The jetson-disk-image-creator.sh script supports use of a modified rootfs. Thus, you can create an SD card image with a specified rootfs directory:

$ ROOTFS_DIR=<MODIFIED_ROOTFS_PATH> ./jetson-disk-image-creator.sh -o <blob_name> -b <board> -r <revision>

To flash the image to an SD card with Etcher¶

Insert the SD card into an SD card slot or an external SD card reader on your host system.
Launch Etcher and select the SD blob image file created by jetson-disk-image-creator.sh.
Select the SD card to be flashed.
Click Flash to write the SD blob image to the SD card.

To flash the image to an SD card with dd¶

Enter the command:
```
$ sudo dd if=<sd_blob_name> of=/dev/mmcblk<n> bs=1M oflag=direct
```
Where:
- <sd_blocb_name> is the name (with pathname, if necessary) of the blob image file created by jetson-disk-image-creator.sh.
- <n> is the SD card block number detected by your Linux host, i.e. 0 or 1.

For example, to copy an image blob file named sd-blob.img from the working directory to SD card block number 1:

$ sudo dd if=sd-blob.img of=/dev/mmcblk1 bs=1M oflag=direct

To resize the root partition to fill available SD card space¶

The root partition is always created at the end of the boot device. This allows you to change its size without moving other partitions.

You change the size of the boot partition with the resize2fs tool, which is run by oem-config the first time a newly copied image blob file is booted from an SD card.

When a freshly initialized SD card is first booted it runs oem-config, one of whose functions is to set the APP partition’s size. It does the following things:

Moves the backup GPT header to the end of the disk
Deletes and re-creates the root partition
Informs the kernel and OS of the change in the partition table and root partition size
Resizes the file system on the root partition to fit the expected partition table and root partition size

Flashing to an External Storage Device¶

The initrd flashing tool supports flashing to an external storage device. For an overview of this tool, see Flashing with initrd.

To flash an external device, you must create an external partition layout. For information about this, see External Storage Device Partition in the topic Boot Architecture.

The devices that Jetson Linux supports as external storage devices are those which appear in the Linux file system as SCSI devices (device name /dev/sd*) and NVMe devices (/dev/nvme*n*) in the Linux “dev” file system. NVIDIA provides the necessary tools and instructions as part of the Linux BSP package; they may be found in the directory Linux_for_Tegra/tools/kernel_flash. For more detailed instructions, see workflows 3, 4, and 5 in the file README_initrd_flash.txt in that directory.

Flashing a Specific Partition¶

You can flash a specific partition instead of flashing the whole device by using the command line option -k.

To flash a specific partition¶

Enter the command:
```
$ sudo ./flash.sh -k <partition_name> [--image <image_name>] <board> <rootdev>
```
Where:
- <partition_name> is the name of the partition to be flashed. Possible values depend on the target device. For specific filenames, see the table of partition configuration files in the topic Partition Configuration.
- <image_name> is the name of the image file. If omitted, flash.sh chooses the image file that was used to flash whole device.
- <board> is the configuration of the target device as specified by the table in Jetson Modules and Configurations in the topic Quick Start
- <rootdev> specifies the device on which the root file system is located, as described in Basic Flashing Script Usage.

Examples¶

To flash the kernel on Jetson AGX Xavier series using the default file <BSP>/kernel/Image, where <BSP> is the directory that contains the Jetson Linux distribution:

$ sudo ./flash.sh -k kernel jetson-xavier mmcblk0p1

To flash MB1_BCT on Jetson AGX Xavier series using a predefined list of configuration files:

$ sudo ./flash.sh -k MB1_BCT jetson-xavier mmcblk0p1

To flash A_MB1_BCT on Jetson AGX Orin series using a predefined list of configuration files:

$ sudo ./flash.sh -k A_MB1_BCT jetson-xavier mmcblk0p1

Flashing for NFS as Root¶

You can flash the device to use a network file system (NFS) as the root file system.

Note

To create a bootable NFS root file system, you must first:

Perform the process described in Step 1: Set Up the Root File System <https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/rootfs_custom.html#wwpID0E0JG0HA>
Perform the process described in Configuring NFS Root on the Linux Host <https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/getting_started.html#wwpID0E0CC0HA>

To flash for a network file system as root file system¶

Put the device into Recovery Mode. Power the carrier board on; press and hold down the RECOVERY button, then press the RESET button.
Enter the command:
```
$ sudo ./flash.sh -N <ip_addr>:<root_path> <board> eth0
```
Where:
- <ip_addr> is the IP address of the host system.
- <root_path> is the path to the NFS root file system.
- <board> is the configuration of the target device as specified by the table in Jetson Modules and Configurations in the topic Quick Start
The command flashes Bootloader and a file system image with a /boot directory only to use the network file system at <ip_addr>:/<root_path> as the root file system at boot time.

Flashing with initrd¶

You can flash with initrd (initial RAM disk) to both internal media and external media connected to a Jetson device. The procedure uses initrd and USB device mode.

Tools and instructions for flashing with initrd may be found in the directory /Linux_for_Tegra/‌tools/‌kernel_flash/. For more detailed information, see README_initrd_flash.txt in the same directory.

README_initrd_flash.txt contains examples several workflows that flash with initrd:

Flashing internal storage devices
Flashing external storage devices such as NVMe SSD and USB drives
Enabling A/B rootfs on external storage devices
Enabling disk encryption on external storage devices
Flashing individual partitions
Flashing fused Jetson devices.
Flashing a Massflash blob to normal and fused Jetson devices
Generating separate images for external and internal storage devices, then flashing the combined images

Note

Jetson AGX Xavier series devices use boot firmware that is stored only on internal eMMC memory. Consequently this type of device can boot from a USB or NVMe drive only if its internal eMMC has been flashed.

Requirements¶

Initrd flash requires a high-quality USB-C / micro-USB cable. (A low-quality cable may make the flashing process fail.)
The host uses NetworkManager, not any other network management application, to configure the network for flashing.
Automount must temporarily be disabled for the new external storage device during flashing. The tool uses USB mass storage during flashing.

On most Debian-based distributions of Linux, you can accomplish this with the command:
```
$ systemctl stop udisks2.service
```

The host must have the following dependencies:

$ sudo apt install libxml2-utils simg2img network-manager abootimg sshpass device-tree-compiler

To flash with initrd¶

Put the Jetson device in Recovery Mode.
Enter these commands on the host:
```
$ cd Linux_for_Tegra
$ sudo ./tools/kernel_flash/l4t_initrd_flash.sh <board-name> <rootdev>
```
Where:
- <board-name> is the value of the environment variable BOARD for the target device. See the table in Jetson Modules and Configurations in the topic Quick Start.
- <rootdev> specifies the device on which the root file system is located, as described in Basic Flashing Script Usage.

Flashing to Multiple Jetson Devices¶

NVIDIA provides a tool and instructions for flashing Jetson devices efficiently in a factory environment. This tool is part of the Linux BSP package and may be found in the directory Linux_for_Tegra. Instructions for using it are in README_Massflash.txt, located in the same directory.

Enlarging an Internal Memory Partition for Root File System¶

Use the flash.sh option -S <size-in-bytes> to change the partition size.

To flash for a larger partition¶

Execute the following command:
```
$ sudo ./flash.sh -S <size> <board> <rootdev>
```
Where:
- <size> is the desired size for the partition, such as 8589934592 (or 8GiB) for 8 GB. The default size of APP is defined in the variable ROOTFSSIZE in the file <board>.conf.
- <board> is the configuration of the target device as specified by the table in Jetson Modules and Configurations in the topic Quick Start.
- <rootdev> specifies the device on which the root file system is located, as described in Basic Flashing Script Usage.

Determining the Success of a Driver Update¶

After updating drivers on a target board, verify that the update completed successfully. You can determine the success or failure of a driver update by using the following commands.

To determine the success of a driver update¶

Execute this command on a booted target device:
```
$ sha1sum –c /etc/nv_tegra_release
```

If the driver update succeeded, the command displays the word “OK” after the file name. A typical success message looks like this:

/usr/lib/xorg/modules/drivers/nvidia_drv.so: OK

The driver update fails if the file is missing. A typical error message looks like this:

sha1sum: /usr/lib/xorg/modules/drivers/nvidia_drv.so: No such file or directory
/usr/lib/xorg/modules/drivers/nvidia_drv.so: FAILED open or read

The driver update also fails if the new file is different from the existing file, producing an error such as:

/usr/lib/xorg/modules/drivers/nvidia_drv.so: FAILED

Reconfiguring a Jetson Device with oem-config¶

A target device that is flashed by SDK Manager runs the oem-config tool automatically the first time it boots after it is flashed. You can use this tool to change some parts of the device’s configuration.

oem-config is useful for custom-configuring production devices. In a typical use case, you flash a default configuration and clone it to many production devices. The purchaser of each device can use oem-config to set their own username and password, language, time zone, and so on.

On a headed target device (one equipped with a display), oem-config runs as a GUI application. On a headless target device (one without a display), it runs as a character interface application which communicates through the flashing port with a terminal program running on the host.

After the target device runs oem-config on first boot, it disables the tool so that it will not run on subsequent boots. If you install your own package and flash the target device manually (outside SDK Manager), you must re-enable oem-config manually if you want it to run on the first subsequent boot. Again, the target device disables oem-config after running it once.

To re-enable oem-config manually on a flash drive¶

Select a source device of the same type as the target device(s), on which all necessary packages have been installed.
Install these packages on the source device to enable oem-config for the next reboot: ubiquity, oem-config, and oem-config-gtk. Enter this command:
```
$ sudo apt-get install --no-install-recommends ubiquity oem-config oem-config-gtk
```

Remove the package nvidia-l4f-oem-config:

$ sudo dpkg --purge nvidia-l4t-oem-config

Clone the source device’s APP partition to backup.img and backup.img.raw. For details, see To clone a Jetson device and flash.
Mount backup.img.raw (an ext4 image file) on the host at a mount point of your choice.
Apply any required Jetson-specific binaries to the image file. The nv-oem-config setup files are included in apply_binaries.sh. To run this script, enter:
```
$ cd Linux_for_Tegra
$ sudo ./apply_binaries.sh -r <root>
```
Where <root> represents the backup.img.raw mount point.

Set nv-oem-config.target as the default.target:

$ cd $root/etc/systemd/system
$ sudo rm default.target
$ sudo ln -s /lib/systemd/system/nv-oem-config.target default.target

Unmount the device mounted in step 5:
```
$ umount $root
```

Make a sparse version of the updated image file backup.img.raw and name it system.img:

$ cd Linux_for_Tegra/bootloader/
$ sudo ./mksparse -v –fillpattern=0 /path/to/backup.img.raw system.img

Flash system.img to the target device(s). For details, see To clone a Jetson device and flash.

To re-enable oem-config manually on an SD card¶

Select a source device of the same type as the target device(s) on which all necessary packages have been installed.
Enter this command to install the following packages on the source device to enable oem-config for the next reboot: ubiquity, oem-config, and oem-config-gtk:
```
$ sudo apt-get install --no-install-recommends ubiquity oem-config oem-config-gtk
```

Remove the package nvidia-l4f-oem-config:

$ sudo dpkg --purge nvidia-l4t-oem-config

Power off the source device and remove the SD card from it, then insert it into in the host system.
Mount partition #1 of the SD card (an ext4 file system) on the host, using a mount point of your choice.
Apply any required Jetson-specific binaries to partition #1 of the SD card. The appropriate files are listed in nv-oem-config, and are applied by apply_binaries.sh. Enter these commands to run the script:
```
$ cd Linux_for_Tegra
$ sudo ./apply_binaries.sh -r <root>
```
Where <root> represents the partition #1 of the SD card mount point.

Set nv-oem-config.target as the default.target:

$ cd $root/etc/systemd/system
$ sudo rm default.target
$ sudo ln -s /lib/systemd/system/nv-oem-config.target default.target

Run jetson-disk-image-creator.sh to create a new SD card image with a modified rootfs:
```
$ cd Linux_for_Tegra/tools
$ sudo ROOTFS_DIR=<root> ./jetson-disk-image-creator.sh -o sd-blob.img -b jetson-nano-devkit -r 100
```
Where <root> represents partition #1 of the SD card on its mount point.For details, see To generate an image to be flashed to an SD card.
Enter this command to unmount the device mounted in step 5:
```
$ umount $root
```
Flash sd-blob.img to the new SD card. For details, see Flashing to an SD Card.

About Communication Through the Debugging Port¶

The terminal program on the host computer customarily communicates with oem-config through the host computer’s tty device and the Jetson device’s flashing port (i.e. the USB port that is used for flashing). See Assumptions in the topic Quick Start.)

Some Jetson developer kits also have a UART port on a 40-pin header. You can edit the oem-config configuration file to make oem-config use this port instead. You must make this change before you flash images on the target device.

To configure oem-config to use a 40-pin header UART port¶

Open the configuration file <top>/etc/nv-oem-config.conf.t194 on the host computer and find the line that defines the property:
```
nv-oem-config-uart-port=ttyGS0
```
Change the value of this property from ttyGS0 to ttyTHS0.
Save and close the configuration file.
Proceed to flash the target device as described elsewhere in this topic.

Headless Mode Flow in oem-config¶

Before the target system boots for the first time, you must start a terminal program on the host computer. You may use putty, screen, or any other program that communicates through the host computer’s tty device and supports the UTF-8 character set.

Note

NVIDIA does not recommend using minicom for this application because it has some issues dealing with UTF-8.

When the target device boots for the first time after flashing and finds no display device, it runs oem-config in headless mode. Use the following procedure to reconfigure the target device.

To reconfigure the target device with oem-config¶

oem-config displays a welcome screen. To advance to the next screen, press Tab, then Enter.
oem-config displays the license that governs its use. Read the license, then accept it by pressing Tab, then Enter.
oem-config displays a screen that lists languages. Use the up and down-arrow keys to select the language you want to use for the installation process. Then press the left and right-arrow keys to select “OK,” and press Enter.

Note

To go back from any screen to the preceding one, select “Cancel” and press Enter. You can go back more than one screen by doing this more than once.

oem-config displays a screen that lists locations in which the language you selected is used. Select your location; then select “OK” and press Enter.
oem-config displays a screen that lists keyboard layouts. Select your keyboard’s layout, then select “OK” and press Enter.
oem-config displays a screen that lists time zones that exist in the location you select. Select your time zone, then select “OK” and press Enter.

If your time zone is not listed, select “Cancel” as many times as necessary to go back to the screen that lists locations, and choose a different location.
oem-config asks whether you want to set the system clock to Universal coordinated Time (UTC, or Greenwich Mean Time). Linux expects the system clock to be set to UTC, so NVIDIA recommends that you select “Yes” and press Enter.
oem-config asks you to enter your name. Enter your full name (e.g. John Smith), then select “OK” and press Enter.
oem-config asks you to enter a username for your user account. oem-config creates a user account with this name. Select “OK” and press Enter.

NVIDIA suggests using your first name, in lower case letters only. Use this account instead of the root account for anything other than administrative activities.
oem-config asks you to enter a password for your user account. Enter a password, then select “OK” and press Enter.

NVIDIA recommends that you choose a strong password, e.g. one that is more than eight characters long and contains at least one each of upper and lower case letters, numerals, and other characters. If you enter a weak password, oem-config asks you to confirm that you want to use it.
oem-config asks you to enter your password again to confirm that you entered it correctly. If you enter the same password both times, it sets the password and goes on to the next step. If not, it prompts you to enter a password again.
oem-config prompts you to create and enable a 4 GB swap file. It first displays a message which summarizes the advantages and disadvantages of doing so:

Read the message and decide whether to create a swap file. Then press Enter to advance to the next screen:

To create and enable a swap file, select “Yes” and press Enter. To skip this step, select “No” and press Enter.

Note

As the “Create Swap File” screen explains, NVIDIA recommends that you create and enable a swap file if you plan to use your Jetson device for artificial intelligence (AI) and deep learning applications.

Note that having a swap file may shorten the life of your SD card, due to increased writes to the medium.

If you do not create a swap file in oem-config, you can later create one manually as described in To create and enable a swap file manually.

oem-config prompts you to specify the desired size of the APP partition in megabytes. To request the maximum possible size, leave the field empty or enter 0 (zero).

To request the maximum possible size, leave the field empty or enter 0 (zero).

Note

This is only for Jetson AGX Orin and Jetson Xavier NX. For the other Jetson devices, you can of course enlarge the APP partition statically with flash option -S.

oem-config displays a list of interfaces which it can use as the primary network interface during installation.

If you are using Ethernet as the primary network interface, make sure that the Ethernet cable is connected. Then select the eth0: Ethernet option, select “OK,” and press Enter.

Note

Due to a known wireless network configuration bug in oem-config, you must either enter the SSID manually instead of selecting it from the list, or wait until after initial setup is complete, then use the nmcli command to configure wireless networking. For more details, see the ubuntu.com documentation page Configure WiFi Connections.

oem-config prompts you to enter your host computer’s host name. If you don’t know the host’s name, ask your network administrator. If you are setting up a dedicated network, you may choose any name. Enter the host name, then select “OK,” and press Enter.
oem-config prompts you to select an nvpmodel mode.

If you don’t know which mode to select, keep the default setting (highlighted on the screen).

You can change the nvpmodel mode at runtime through the nvpmodel GUI tool. For more information, go to the topic Clocks, and read the “nvpmodel GUI” subsection in the appropriate “Power Management” section for your Jetson platform.
oem-config prompts you to install Chromium Browser right now. Internet connection is required for installation, and it will take several minutes to install.

Read the message and decide whether to install Chromium Browser. Then press Enter to advance to the next screen:

To install Chromium Browser, select “Yes” and press Enter. To skip this step, select “No” and press Enter.
oem-config reconfigures the system with the selections you have made, then proceeds to the system’s log-in prompt.

To create and enable a swap file manually¶

This procedure is an alternative to step 12 of To reconfigure the target device with oem-config. You may perform it at any time after you run oem-config.

To create the swap file, enter the commands:

$ sudo fallocate -l 4G /swapfile
$ sudo chmod 600 /swapfile
$ sudo mkswap /swapfile
$ sudo swapon /swapfile

To automount the swap file on boot, open /etc/fstab in a text editor, add this line, and save:
```
/swapfile swap swap defaults 0 0
```

Note

The fields in this line may be separated by any combination and number of tabs and spaces. NVIDIA recommends spacing the fields to align with the fields in the file’s other lines.

Skipping oem-config¶

If you don’t want to run oem-config to set up your system, you can make the first-time boot process skip it by running the host script l4t_create_default_user.sh before you flash. The boot process runs oem-config if no default user is defined; l4t_create_default_user.sh creates a default user, and thus prevents oem-config from running.

The script’s usage is:

$ l4t_create_default_user.sh [-u <user>] [-p <pswd>] [-n <host>] [-a] [-h]

This table describes the command line options:

Command line option	Description
-u <user> –username <user>	Creates a default user with the specified username. If omitted, the script creates a default user named `nvidia`.
-p <pswd> –password <pswd>	Creates the default user with the specified password. If omitted, the script generates a random password.
-n <host> –hostname <host>	Creates the default user with the specified host name. If omitted, the script uses the host name `tegra-ubuntu.`
-n <host> –hostname <host>
-a –autologin	Configures Jetson Linux to log in to the default user automatically when booted. If omitted, the user must log in manually.
–accept-license	Accepts the EULA for NVIDIA software. If omitted, the script prompts you to accept the EULA.
-h –help	Prints a description of the script’s usage.

Examples¶

Create a user named nvidia with the password NDZjMWM4 and the host name tegra-ubuntu:
```
$ l4t_create_default_user.sh -u nvidia -p NDZjMWM4
```
Create a user named ubuntu with a randomly generated password and the host name tegra-ubuntu, and configures Jetson Linux to log in to it automatically at boot:
```
$ l4t_create_default_user.sh -u ubuntu -a
```
Create a user named nvidia with a randomly generated password and the host name tegra:
```
$ l4t_create_default_user.sh -n tegra
```

Modifying Jetson RAM Disk¶

Use the following procedure to modify the default configuration of a Jetson device’s RAM disk.

To modify RAM disk¶

Unpack your initrd:

$ sudo su
$ cp /boot/initrd /tmp
$ mkdir /tmp/temp
$ cd /tmp/temp
$ gunzip -c /tmp/initrd | cpio -i

Modify your initrd content in the tmp/temp/ directory according to your needs

Package your initrd:

$ sudo su
$ cd /tmp/temp
$ find . | cpio -H newc -o | gzip -9 -n > ../initrd

Replace the initrd with your customized initrd:
```
$ cp /tmp/initrd /boot/initrd
```