Juniper SRX 345

Juniper SRX – Upgrading JunOS from USB

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There’s a few ways to do this. Here’s the easiest:

First, format your USB drive as fat32. Download the compressed image from Juniper (e.g. junos-srxsme-15.1X49-D80.4-domestic.tgz) and load it onto the USB drive.

Whilst logged into the SRX’s console, plug in the USB drive. You’ll see something like the below:

umass1: TOSHIBA TransMemory, rev 2.00/1.00, addr 2
da1 at umass-sim1 bus 1 target 0 lun 0
da1: <TOSHIBA TransMemory 1.00> Removable Direct Access SCSI-4 device
da1: 40.000MB/s transfers
da1: 7400MB (15155200 512 byte sectors: 255H 63S/T 943C)

This tells you that the USB drive is available at /dev/da1. Assuming your drive has a single partition, that means the filesystem will be at /dev/da1.

Jump into the FreeBSD shell:

start shell

Create a directory and mount the USB drive to it:

mkdir /var/tmp/usb/
mount_msdosfs /dev/da1 /var/tmp/usb/

Check that your JunOS image is present on the mount:

root@% ls -1 /var/tmp/usb/

Jump back to the main JunOS console:


Install the image:

request system software add no-copy no-validate /var/tmp/usb/junos-srxsme-15.1X49-D80.4-domestic.tgz

Reboot your device:

request system reboot in 0

Once rebooted, sanity check your new install. If all is ok, you need to copy the JunOS image to the backup partition else if your SRX ever fails to boot then it will boot into your old JunOS:

request system snapshot slice alternate

Once done, you can check it:

root> show system software
Information for junos:

JUNOS Software Release [15.1X49-D80.4]

root> show system software backup
Backup JUNOS package information:
File name: /altroot/cf/packages/junos-15.1X49-D80.4-domestic
File size: 249978054

And that’s it.


  1. Great Article. Where I could pack a copy of the junos for my SRX210 juniper. I do not have enough privileges to download the updates.

    Thanks Cesario

    1. If you have a support contract on any Juniper device (with Juniper or a partner), give Juniper a call and they’ll give you access to all the JunOS releases for all devices.

  2. very informative Artical.
    Thanks for sharing knowledge.
    Sir i’ve SRX550, i’ve recently upgraded it’s OS, now i am trying to configure it but at the time of saving it gives error “The configuration could not be un-locked. Error(s):1) syntax error Name error”

    kindly guide
    Best Regards

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