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Installing Software on ACX Series Routers (Junos OS)

ACX Series routers are delivered with preinstalled Junos operating system (Junos OS). Before you start this procedure, decide which software package you need and download it. For information on which packages to use for which upgrades, see Junos OS Installation Package Names.

Installing Junos OS Using a USB Storage Device on ACX Series Routers

To install the Junos OS image on ACX Series routers using a USB storage device, you must have access to the USB port physically and you must also have console access. Perform the following steps to install the Junos OS image:

  1. Insert the USB storage device that has a valid installation image into the USB port.
  2. Reboot the router by either pressing the power button on the chassis or switching off and turning on the power button behind the Routing Engine, or by entering the request system reboot command from the CLI. The system LED starts blinking in green.

    On the console, a message is displayed stating that your flash memory device (NAND Flash device) will be formatted and you will lose all the data. You are prompted to confirm the formatting of the flash memory device.

  3. Press y to confirm and proceed with the formatting process. The flash memory device is formatted and the image is installed on both the partitions.

    After the installation is completed, a message is displayed on the console prompting you to eject the USB storage device and to press Enter to reboot the device.

  4. After you remove the USB port and press Enter, the reboot begins. After the router is rebooted, the new Junos OS version is loaded and functional. The LED glows steadily in green.

If an installation error occurs, the LEDs turn red. You must have console access to the router to troubleshoot an installation error.

Installing Junos OS Upgrades from a Remote Server on ACX Series Routers

You can use the CLI to install Junos OS packages that are downloaded with FTP or HTTP from the specified location on internal media, such as the NAND Flash device.

Before you begin:

  • Verify the available space on the NAND Flash device.

  • Download the Junos OS package.

To install Junos OS upgrades from a remote server, enter the following command from operational mode:

The new Junos OS image is installed on the router and the device is rebooted.


On ACX5048 and ACX5096 routers, use the force-host option to force installing the latest version of the Host OS.