Convert ASA 5516-X back to ASA from FTD

If you received a ASA 5500-X series firewall that is running FTD instead of ASA and you want to roll it back to ASA, (or you upgraded to FTD and decided it’s not for you and want to go back to the ASA OS) then you are in the right place.

We recently purchased a few Cisco ASA 5516-X firewalls for various things and all of them shipped to us with FTD on them, even though we specified ASA. I guess Cisco really wanted us to try out FTD. Where these are going, FTD isn’t something we need, so…. No.

Alright, lets look at what is required to get this baby back to good ol’ ASA software.


You MUST have:

  • A TFTP server accessible by your firewall. You can use something like Solarwinds Free TFTP server installed on your workstation (don’t forget to allow the port through your Windows firewall if applicable) that you plug into the firewall. I personally use the TFTP server built into my Solarwinds NCM server (I don’t know how I ever worked without NCM) that can be reached by my lab environment.
  • A console/serial/rollover cable
  • Terminal software such as PuTTY
  • The official ASA software from Cisco that you want to run on your firewall.
  • The official ASDM software from Cisco that you want to manage your firewall with.
  • The activation code for your firewall if you licensed any features above the 3DES/AES feature set (I’ll show you below how to retrieve your 3DES/AES license).

Let’s get started!

Steps to Convert ASA5500-X from FTD to ASA Image

  1. Connect the management port of your firewall to your workstation that is running the tftp software (or a switch that can access your tftp server).
  2. Connect your workstation to the console port of the firewall using a serial/rollover cable.
  3. Connect to your firewall using your terminal emulator software such as PuTTY.
  4. Login to the FTD appliance.
    1. If this is a new FTD install on a recent software version the default credentials should be:
      1. Username: admin
      2. Password: Admin123
  5. Proceed through any EULAs and basic config wizard steps (if this is a new FTD install) and then reboot the ASA firewall using the ‘reboot’ command.
    firepower login: admin
    Last login: Tue Nov 3 17:17:52 UTC 2020 on ttyS1Copyright 2004-2019, Cisco and/or its affiliates. All rights reserved.
    Cisco is a registered trademark of Cisco Systems, Inc.
    All other trademarks are property of their respective owners.
    Cisco Fire Linux OS v6.5.0 (build 4)
    Cisco ASA5516-X Threat Defense v6.5.0 (build 115)
    > reboot
    This command will reboot the system.  Continue?
    Please enter 'YES' or 'NO': YES
  6. As the ASA is booting back up, interrupt the boot process by pressing ‘break’ or ‘esc’ to drop into rommon.
    Cisco Systems ROMMON, Version 1.1.15, RELEASE SOFTWARE
    Copyright (c) 1994-2019 by Cisco Systems, Inc.
    Compiled Sat 03/30/2019 7:00:46.51 by wchen64Current image running: Boot ROM0
    Last reset cause: PowerCycleRequest
    DIMM Slot 0 : Present
    DIMM Slot 1 : PresentPlatform ASA5516 with 8192 Mbytes of main memory
    MAC Address: bc:5a:22:22:22:22
    Use BREAK or ESC to interrupt boot.
    Use SPACE to begin boot immediately.
    Boot interrupted.
  7. Erase the onboard flash drive.
    rommon 1 > erase disk0:
    erase: Erasing 7039 MBytes ..............
  8. Note: If you’re reverting a 5516-x, 5508-x, or 5506-x, you do not need to specify an interface at this step as it will use the management interface by default. If you’re re-imaging a different model, set the interface that is connected to your switch or tftp server.
    rommon 2 > interface gigabitethernet0/1
  9. Set the address of your ASA so it can talk to your switch or tftp server.
    rommon 2 > address
  10. Set the subnet mask.
    rommon 3 > netmask
  11. Set the ip address of your tftp server.
    rommon 4 > server
  12. Set the gateway of your ASA.
    rommon 5 > gateway
  13. Set the name of ASA image file that is on your tftp server.
    rommon 6 > file asa9-13-1-lfbff-k8.SPA
  14. Verify your network settings by running the ‘set’ command.
    rommon 7 > set
    PS1="rommon ! > "
  15. Save your settings by entering the ‘sync’ command.
    rommon 8 > sync
  16. Download and boot to the ASA image by running the ‘tftpdnld’ command.
    rommon 9 > tftpdnld
    IMAGE: asa9-13-1-lfbff-k8.SPA 
    MACADDR: bc:5a:56:65:9a:89 
    VERBOSITY: Progress 
    RETRY: 40 
    PKTTIMEOUT: 7200 
    BLKSIZE: 1460 
    CHECKSUM: Yes 
    PORT: GbE/1 
    PHYMODE: Auto Detect
    Receiving asa9-13-1-lfbff-k8.SPA from!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    File reception completed.

The ASA will now boot up to the image you specified but it will be running in volatile memory so we need to format the flash drive so we can save the permanent copy of the software and make room to save the running config to a startup config.

  1. Once booted up, the ASA will ask you if you wish to use the wizard to configure the management information of the firewall. Proceed if you wish, or skip if you want to set this up later.
    Pre-configure Firewall now through interactive prompts [yes]? *return*
    Firewall Mode [Routed]: *return*
    Enable password [<use current password>]: 
    Allow password recovery [yes]? *return*
    Clock (UTC): *return*
    Year [2020]: *return*
    Month [Dec]: *return*
    Day [11]: 11 
    Time [22:01:34]: 15:16:00 
    Management IP address: 
    Management network mask: 
    Host name: ciscoasa 
    Domain name: npg.local 
    IP address of host running Device Manager:
    Use this configuration and save to flash? [yes] *return*
    INFO: Security level for "management" set to 0 by default. 
    Cryptochecksum: 902d819c 60747c03 9855c56b 8d46eb12
    3014 bytes copied in 0.70 secs
    Insufficient flash space available for this request: 
    Size info: request: 41 free:0 delta:41 
    Insufficient flash space available for this request: 
    Size info: request:32 free:0 delta:32
    ERROR: Inspect configuration of this type exists, first remove that configuration and then add the new configuration
    User enable_1 logged in to ciscoasa 
    Logins over the last 1 days: 1. Failed logins since the last login: 0. Type help or '?' for a list of available commands.
  2. Enter ‘enable’ to enter enable mode.
    ciscoasa> enable
  3. Format the disk using the ‘format disk0:’ command.
    ciscoasa(config)# format disk0:
    Format operation may take a while. Continue? [confirm] *return*
    Format operation will destroy all data in "disk0:". Continue? [confirm] *return*
    Initializing partition - done!
    Creating FAT32 filesystem
    mkfs.fat 3.0.28 (2015-05-16)
    System tables written to disk
    Format of disk0 complete
  4.  Assuming you configured the interface settings earlier, it’s time to TFTP the permanent copy of the OS to the flash drive.
    ciscoasa# copy tftp disk0:
    Address or name of remote host?
    Source filename? asa9-13-1-lfbff-k8.SPA
    Destination filename? asa9-13-1-lfbff-k8.SPA
    Accessing tftp://!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    Verifying file disk0:/asa9-13-1-lfbff-k8.SPA...
    Writing file disk0:/asa9-13-1-lfbff-k8.SPA...107543456 bytes copied in 36.510 secs (2987318 bytes/sec)
  5. Set the copied OS as the boot image.
    ciscoasa(config)# boot system disk0:/asa9-13-1-lfbff-k8.SPA
  6. Use TFTP to copy the ASDM software to the flash.
    ciscoasa# copy tftp disk0:
    Address or name of remote host []? *return*
    Source filename [asa9-13-1-lfbff-k8.SPA]? asdm-7141-48.bin
    Destination filename [asdm-7141-48.bin]? *return*
    Accessing tftp://!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    Verifying file disk0:/asdm-7141-48.bin...
    Writing file disk0:/asdm-7141-48.bin...INFO: No digital signature found
    35744052 bytes copied in 13.790 secs (2749542 bytes/sec)
  7. Set the copied ASDM image as the ASDM image:
    ciscoasa# conf t
    ciscoasa(config)# asdm image disk0:/asdm-7141-48.bin
  8. Write the current running config to flash memory
    ciscoasa# write memory

It’s at this point you would enter a license feature activation key if you had one saved (config t command ‘activation-key **key**’). I don’t have this so I will skip that. However, I do need to enable 3DES/AES using Cisco’s Free License to give me back the crypto features that come with the ASA5516-FPWR-K9 SKU. So let me step you through that process.

  1. Open a web browser and go to Cisco’s licensing portal at
  2. Choose your Smart Account, if applicable
  3. Choose your Virtual Account, if applicable
  4. Navigate to Licenses -> Get Licenses -> IPS, Crypto, other…

  5. Click Next.
  6. Choose Security Products -> Cisco ASA 3DES/AES License

  7. Click Next.
  8. Enter the serial number of your ASA from the ‘show version‘ or ‘show module‘ commands.
  9. Click Next.
  10. Verify your information and click Submit.
  11. Check your invox for an email containing the activation key.
  12. On your ASA run the ‘activation-key’ command in config mode followed by the provided key.
    ciscoasa(config)# activation-key 584hd835 496kgf03 34343678 8556kkr5 8214df45
  13. Run the command ‘show version’ and verify the Encryption-3DES-AES now shows as Enabled
    Licensed features for this platform:
    Maximum Physical Interfaces       : Unlimited      perpetual
    Maximum VLANs                     : 150            perpetual
    Inside Hosts                      : Unlimited      perpetual
    Failover                          : Active/Active  perpetual
    Encryption-DES                    : Enabled        perpetual
    Encryption-3DES-AES               : Enabled        perpetual
    Security Contexts                 : 2              perpetual
    Carrier                           : Disabled       perpetual
    AnyConnect Premium Peers          : 4              perpetual
    AnyConnect Essentials             : Disabled       perpetual
    Other VPN Peers                   : 300            perpetual
    Total VPN Peers                   : 300            perpetual
    AnyConnect for Mobile             : Disabled       perpetual
    AnyConnect for Cisco VPN Phone    : Disabled       perpetual
    Advanced Endpoint Assessment      : Disabled       perpetual
    Shared License                    : Disabled       perpetual
    Total TLS Proxy Sessions          : 1000           perpetual
    Botnet Traffic Filter             : Disabled       perpetual
    Cluster                           : Enabled        perpetual
    Cluster Members                   : 2              perpetual
    VPN Load Balancing                : Enabled        perpetual

And that’s it! You should be back to good ol’ ASA now and can finally start setting it up.

Recommended for You: Solarwinds Network Configuration Manager (NCM)

What would you do if one of your pieces of networking equipment failed? Could you rebuild it quickly? Do you know exactly what configuration it had? What ports were on what vlan? What about port channels?

You get the point.

Automate backing up configurations and updating of all your switching, routing, and firewall equipment without needing to know a single line of code with Solarwinds Network Configuration Manager.

This is one of those tools that pays for itself in man hours the first time you need to rely on it. Plus, you’ll sleep easier knowing you really have backed up all the things.

Chase Smith, CCNP

Chase Smith, CCNP is a Network Engineer III who has spent the last decade elbow deep in enterprise system administration and networking. He can usually be found trying to warm up behind the storage in the datacenter.

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