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[EX] How to recover EX2300s and EX3400s with format install procedure via TFTP



Article ID: KB31462 KB Last Updated: 28 Mar 2020Version: 3.0

EX2300 and EX3400 series switches can be recovered by performing a format install from TFTP server if the switch does not boot successfully. This article describes the procedure.

Note: This procedure will format the switch and all configurations will be lost.

For USB format install steps, refer to KB31265 - [EX] How to format install on EX2300 and EX3400.



Note: This procedure will format the switch and all configurations will be lost.

  1. Download the image from Juniper's support site. Be sure to download the install media image; the file format is tgz.

  2. Copy the required image on the TFTP server to the required directory.

  3. Reboot the switch and interrupt the boot sequence:

    a. Press any key when you see Main Menu to avoid auto boot
    b. Stop at uboot (^C or space to stop autoboot –depending on the uboot version; for older uboot -> press space)

  4. Set the switch-management IP address, netmask and gateway IP
    => setenv ipaddr
    => setenv gatewayip
    => setenv netmask
    => setenv serverip
    => save


    Ping the server to see if is reachable:

    => ping
    Using FM1@DTSEC1 device
    host is alive


  5. Reboot the switch and interrupt to navigate to OAM menu. Choose option 5.  [M]ore options and then option 5.  [B]oot prompt, which will take you to the loader:

    a. To reboot the switch from u-boot mode:

    => boot
    b. To navigate to OAM menu:

    Press control+c / ^C or space to stop autoboot

    Main Menu

    1.  Boot [J]unos volume
    2.  Boot Junos volume in [S]afe mode
    3.  [R]eboot
    4.  [B]oot menu
    5.  [M]ore options

    Options Menu

    1.  Recover [J]unos volume
    2.  Recovery mode - [C]LI
    3.  Check [F]ile system
    4.  Enable [V]erbose boot
    5.  [B]oot prompt
    6.  [M]ain menu

  6. Issue the install command with the format option to install the Junos image via TFTP: 

    loader> install --format tftp://

  7. After TFTP installation is done, log in and verify that the new version of the software is properly installed.


Modification History:

2020-03-28: Added link to KB31265 in Summary

2018-10-28: Corrected typo; changed 'etenv netmask' to 'setenv netmask' in step 4


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