1. Reboot device
2. At prompt, hit escape to break the boot sequence
3. 'confreg' !! prompt will start with 'rommon #'
4. Note your current configuration register (0x1 is the default)
5. Choose 'Y' to change the configuration
6. Accept all the defaults EXCEPT 'disable system configuration'. Set this to 'Y'
7. 'boot'
8. 'enable' after device has booted !! Just hit enter for the password
9. 'copy startup-config running-config'

10. Reset the passwords in 'conf t':

    password <password> enable password <password> username <username> password <password>

11. 'config-register
12. 'copy running-config startup-config'

Notes:

• Must be performed via the console port

Documentation