Install Junos OS on SRX300 Line of Firewalls Using a USB Flash Drive

Learn how to install Junos OS on SRX Series Firewalls using a USB flash drive. This process includes upgrade prerequisites, boot loader updates, and step-by-step installation procedures.

Prerequisites Before Installation

When you upgrade or downgrade SRX300 line of Firewalls to Junos OS Release 24.4R1 using a USB flash drive, the device reboots and comes up in amnesiac state. Therefore, before you install, ensure that you have saved the configuration file so that you can easily reconfigure the device using the console port if required.

Before you upgrade from either Junos OS Release 23.4R2-S3 or from Release 24.2R2 to Junos OS Release 24.4R1 for SRX300 Line of Firewalls, complete the following tasks:

Upgrade the universal boot loader (U-Boot) software to at least version 3.15.
Upgrade the loader to a build from the year 2023 or later. During the boot process, the loader reveals the build date. For example, this loader was built on May 23, 2023.

Once you have installed either Junos OS Release 23.4R2-S3 or Release 24.2R2, the Junos OS image contains the latest boot loader binaries in the paths: /boot/uboot and /boot/veloader. You can upgrade the U-Boot software and veloader with the following steps:

From the CLI prompt, enter the start shell command.
From the shell prompt, update the U-Boot software with the bootupgrade -u /boot/uboot command.
From the shell prompt, update the veloader with the bootupgrade -l /boot/veloader -x command.
Reboot the device. When the device is up, you can use a USB flash drive to upgrade to Junos OS Release 24.4R1.

Install Junos OS on a Flash Drive

To install the Junos OS image on an SRX Series Firewall using a USB flash drive, follow the below steps:

Insert the USB flash drive into the USB port of the SRX Series Firewall and observe the LEDs.

The LEDs will initially blink amber and then steadily turn amber, indicating that the SRX Series device has detected the Junos OS image.
Press the Reset Config button on the SRX Series Firewall to initiate the installation process.

The LEDs glow steadily amber during installation.
Remove the USB flash drive.

Frequent plugging and unplugging of USB storage device is not supported. Always wait for device recognition before removing the drive.
Wait for the device to complete the installation.
- The SRX Series Firewall restarts automatically after installation.
- The LEDs glow green when the new Junos OS version is successfully installed.

If the LEDs do not change to amber:

Press the Power button or restart the device.
Wait for the LEDs to blink amber before attempting again.

During installation, if an error occurs, the LEDs turn red. Common reasons are:

Error Cause	Description
Corrupted Junos OS image	The image file on the USB flash drive is corrupted.
Configuration incompatibility	The existing configuration is incompatible with the new OS version.
Insufficient storage	Not enough space on the device to install the image.

In case of errors, you require console access to troubleshoot.

Additional Behavior During Installation

When a USB storage device is inserted, the Reset Config button functions only for image upgrade.
Other Reset Config button operations are overridden until the USB storage drive is removed.
You do not need to wait for LEDs to turn steadily amber before pressing Reset Config; press the button when LEDs blink amber to avoid unnecessary delays.

You can use the set system autoinstallation usb disable command to prevent the automatic installation from the USB storage device. After using this command, if you insert the USB storage device into the USB port of the SRX Series Firewall, the installation process does not work.

Use Feature Explorer to confirm platform and release support for specific features.

Review the Platform-Specific USB Flash Drive Behavior section for notes related to your platform.

Platform-Specific USB Flash Drive Behavior