Cisco Nexus 9000 Series NX-OS Software Upgrade and Downgrade Guide, Release 10.6(x)

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Convert a Nexus 9000 Series switch back to NX-OS

Updated: February 5, 2026

Overview

Learn how to convert a Nexus 9000 Series switch from ACI boot mode back to NX-OS standalone mode by reformatting the file system and booting the standalone software image. This process includes using the loader prompt to initialize the system and configuring boot variables through TFTP or USB recovery methods.

You can convert a Nexus 9000 Series switch from Application Centric Infrastructure (ACI) boot mode back to NX-OS.

Note

When converting any switch from ACI to NX-OS (standalone) boot mode, you can delete the ACI image from the bootflash to save space.

Procedure

1.

Reload the switch.

Example:

switch# reload
2.

During the initial boot sequence, enter a break sequence (Ctrl-C or Ctrl-]) to access the loader> prompt.

Example:

Ctrl-C
loader>
3.

Configure the boot process to stop at the boot prompt.

Example:

loader> cmdline recoverymode=1
4.

Boot the active supervisor module with the NX-OS image.

Example:

loader> boot nxos.9.2.3.bin
Note

If the NX-OS image that is mentioned in the boot variable is not present in the bootflash, the system falls back to the loader prompt during the boot sequence. To recover the switch from the loader prompt, boot the system through a different image present in the bootflash, perform a tftpboot , or boot through a USB device.

Note

For some NX-OS releases and Nexus 9000 Series switches, a sample error message that appears is

!!Fatal error!!
Can't reserve space for RPM repo
Please free up bootflash space and reboot

If you see this error message, start over from Step 1. After Step 3, enter the cmdline init_system command and then go to Step 4. The switch boots into the normal NX-OS prompt and skips the switch(boot)# prompt.
5.

Restore the switch file system partitioning to the default settings. The bootflash filesystem is reset to NX-OS partitioning, and the NX-OS image is deleted.

Example:

switch(boot)# init system
6.

Complete the upload of the NX-OS image file.

Example:

switch(boot)# load-nxos
Note

For some Nexus 9000 Series switches, the device does not load with the normal NX-OS prompt (switch#) and instead comes up as bash-4.2#. In this case, you must power cycle the device, jump to loader, and boot the NX-OS image using either TFTP or a USB method.

  • For the TFTP method - First assign an IP address and gateway to the device using the set ipip addresssubnet mask and the set gwgateway address commands. This is required as the init system command in the above step erases all available configurations on the device

    Example
    loader> set ip 192.0.2.10 255.255.255.0
loader> set gw 192.0.2.1

    Then use the tftp command to load the image.

    loader> boot tftp://<tftp server ip>/<nxos-image-name>

  • For the USB method - Mount the USB on the switch and execute the dir command on the loader to see the contents of the bootflash folder and the USB device.

    Example
    loader > dir
usb1::
lost+found
/nxos.9.x.y.bin

    Then boot the NX-OS image using the following command:

    loader> boot usb1:/nxos-image
Example: boot usb1:/nxos.9.x.y.bin

After you boot the NX-OS image, the device loads as a NX-OS switch and you can continue with the remaining steps.
7.

Copy the NX-OS image into the bootflash: and set the appropriate boot variables to ensure that the system boots the NX-OS image on the next reload.

Example:

TFTP example:

switch# copy tftp://tftp-server-ip/nxos-image-namebootflash:

switch# configure terminal

switch(config)# boot nxos bootflash:nxos-image-name

switch(config)# copy running-config startup-config
switch(config)# end

USB example:

switch# copy usb1:nxos-image-namebootflash:

switch# configure terminal
switch(config)# boot nxos bootflash:nxos-image-name
switch(config)# copy running-config startup-config
switch(config)# end
8.

Wait for the system controllers to come up (approximately 15–20 minutes).

File system differences between ACI and NX-OS require one-time reformatting change during the ACI to NX-OS conversion. Subsequent reloads with the NX-OS image are faster.
9.

Verify that the active supervisor module and the system controllers are in the active state.

Example:

switch# show module
Note

  • For dual-supervisor systems, follow Steps 3–6 on the standby supervisor.

  • Log in to the switch and verify that it is running NX-OS software.

Load NX-OS image into bootflash using SCP on the ACI shell

If you have a Nexus 9000 Series Switch in ACI mode and must convert it to NX-OS mode but are unable to perform a TFTP boot and physical access to USB is not available, then Secure Copy Protocol (SCP) can be used on the ACI Shell to load a NX-OS Image into the bootflash. Contact TAC for further information about the process, as this requires root access.