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How to create a bootable USB install media on MX150



Article ID: KB32655 KB Last Updated: 26 Oct 2020Version: 3.0

This article explains how to make an install-media USB disk from MX150 platform.


The following procedure allows users to create an install media on MX150 devices.

Note: The USB drive is detected on Linux host side /dev directory, not on FreeBSD(Junos VM) /dev directory. The example below uses "install-media-host-usb-mx100-x86-64-17.4R1.16-secure.img" as the install media image file name.

  1. Store the MX150 install media image file to MX150 box (in Junos CLI).
    user@mx150> start shell
    % scp <your_server_username>@<your_server_address>:install-media-host-usb-mx100-x86-64-17.4R1.16-secure.img /var/tmp/
    user@'s password:
    % ls -l /var/tmp/
    -rw-r--r--  1 root     20  1887436800 Dec 21 22:11 install-media-host-usb-mx100-x86-64-17.4R1.16-secure.img
  2. Move to Linux host prompt. "" is a fixed address for Linux host via internal connection.
    % ssh -JU __juniper_private4__ root@
    Last login: Tue Apr 17 09:52:43 2018 from mx150
    root@mx150-node:~#   <-- "-node" indicates you're in Linux host shell

    Note: Unless you're logging in as root user on Junos, you need to specify username as "root@" in ssh command.

  3. Insert USB stick to MX150 box USB port. You can check the disk partition of USB from dmesg.
    root@mx150-node:~# dmesg | grep -i scsi
    [600876.608516] scsi7 : usb-storage 3-1:1.0
    [600877.608645] scsi 7:0:0:0: Direct-Access     SanDisk  Cruzer Blade     1.27 PQ: 0 ANSI: 6
    [600877.616627] sd 7:0:0:0: [sdb] Attached SCSI removable disk <-- [sdb] is the device name

    Note: Or, you can check the disk partition of USB by lsblk command as well.
    root@mx150-node:~# lsblk -S
    NAME HCTL       TYPE VENDOR   MODEL             REV TRAN
    sda  0:0:0:0    disk ATA      StorFly VSFBM6CC 0629 sata
    sdb  7:0:0:0    disk SanDisk  Cruzer Blade     1.27 usb  <--  sdb shows usb transport type
  4. Copy the install media image file from Junos VM to Linux host. "" is fixed address for Junos VM via internal connection.
    root@mx150-node:~# scp <username>@ /var/tmp/
    root@mx150-node:~# ls -l /var/tmp/
    -rw-r--r-- 1 root root 1887436800 Apr 18 18:49 install-media-host-usb-mx100-x86-64-17.4R1.16-secure.img

    Note: The install media image is huge, so it is better to put the file in /var/tmp directory.

  5. Copy the image block by block with the following dd command.

        dd if=/dev/zero of=/dev/<disk_partition> bs=1M count=20
        dd if=<file_name> of=/dev/<disk_partition> bs=1M
    root@mx150-node:~# dd if=/dev/zero of=/dev/sdb bs=1M count=20
    20+0 records in
    20+0 records out
    20971520 bytes (21 MB) copied, 0.015077 s, 1.4 GB/s
    root@mx150-node:~# dd if=/var/tmp/install-media-host-usb-mx100-x86-64-17.4R1.16-secure.img of=/dev/sdb bs=1M
    1800+0 records in
    1800+0 records out
    1887436800 bytes (1.9 GB) copied, 1.13771 s, 1.7 GB/s
  6. Eject the install USB media.

    [Option] When you boot with install media in MX150 in order to recover, you need to run the reboot command in Linux host side. Or power cycle for the MX150 box. If you reboot only in Junos, it does not start USB boot menu.
    root@mx150-node:~# reboot
    INIT: Sending processes the TERM signal
Modification History:
2020-10-26: Article reviewed for accuracy, no changes required; article accurate and valid

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