Cisco

Cisco FPR4120 Password Recovery

Step-by-step password recovery for the Cisco FPR4120 (Firepower 4100/9300 (FXOS)). Console access required.

Overview

This guide provides step-by-step instructions for resetting lost or forgotten administrative passwords on enterprise networking hardware. Follow the procedure below carefully to regain access while preserving your device configuration.

Prerequisites

Before proceeding with password recovery, ensure you have a console cable, terminal emulation software configured to 9600 baud, and physical access to the device.

Step 1: Establish Console Connection

Connect your terminal cable to the console port of the device and open your serial terminal session.

Step 2: Interrupt the Boot Sequence

Power cycle the hardware and issue a Break key sequence during initial system startup to enter ROMMON mode.

Step 3: Reset Password & Configuration

Bypass startup configuration loading, boot into system software, set your new credentials, and save changes back to non-volatile memory.

Overview

This procedure recovers administrator access to the Cisco Firepower 4120 (Cisco Firepower Threat Defense, FTD, running on FXOS). FTD password recovery is handled through the FXOS chassis manager and the FTD CLI — it is different from classic ASA recovery.

Prerequisites

Console cable with a terminal session at 9600 baud, 8N1. Physical or remote power access to reboot the appliance.

Recovery Procedure — FXOS Local Management Method

Connect the console cable and open a terminal session (9600 8N1).
If you can reach the FXOS CLI (via console or SSH to the management interface), skip to step 5. Otherwise reboot the appliance and log in to FXOS with the FXOS credentials (admin password is set during initial setup — if lost, proceed to the boot menu method below).
From the FXOS CLI, enter local management (the FTD management shell): connect local-mgmt.
Reset the FTD admin password: passwd admin — follow the prompts to set a new password.
Exit local management: exit. The new password applies to FTD SSH/console access (admin user).

Recovery Procedure — FXOS Boot Menu Method (when FXOS password is also lost)

Connect the console cable (9600 8N1).
Reboot the appliance.
During the FXOS boot, when prompted, press the key to enter the boot menu (on Firepower 1000/2100, press any key when "Press any key to stop autoboot" appears; on FPR 4100/9300, the boot menu is reached via the CIMC/console).
From the FXOS boot menu, select the option to boot the FXOS image, then interrupt the boot at the GRUB menu.
At the GRUB menu, append single (or init=/bin/bash) to the kernel command line and boot. This drops you to a root shell on the FXOS partition.
Mount the root filesystem read-write: mount -o remount,rw /
Reset the admin password: passwd admin (or edit the shadow file if passwd is unavailable).
Reboot: reboot. Log in to FXOS with the new password, then use connect local-mgmt → passwd admin to also reset the FTD-side admin password.

Important Notes

FTD has TWO admin accounts: the FXOS admin (chassis level) and the FTD admin (the firewall management shell). Both may need resetting; connect local-mgmt bridges from FXOS to the FTD shell.
On Firepower 4100/9300 (FPR4xxx/FPR9300), the console boots into FXOS; the CIMC (IPMI-based management) also provides console access.
If FTD was deployed in multi-instance mode, reset each instance's admin password from its own local-mgmt context.
This procedure does not erase the FTD configuration — only passwords are changed. (A full factory reset via factory reset in FXOS is available as a last resort but wipes all config.)
Baud rate is 9600 on Firepower appliances.

Protecting Your Configuration

Before recovery, export the FTD config: show running-config captured to a file, or backup via the FMC (Firepower Management Center). Document the FXOS admin password separately — losing both FXOS and FTD passwords makes recovery significantly harder.