Resetting Cisco Password via ROMMON

I got myself a second hand Cisco 2811 router. When it arrived, I need to gain access so I have to recover or reset the password to something I know.  What best way than to reset it via ROMMON?

I used my laptop and a terminal software. For me, I used my favorite free software putty.exe you can download from this link. I then connect the console of the Router to my laptop via a USB-to-Serial adaptor from Prolific as my laptop do not have a serial port. Once the serial port assigned to the USB-to-Serial adaptor is identied, I set the Putty to connect in serial mode at 9600 baud and 8 bit no parity and 1 stop bit. In my case, my USB-to-Serial adapter was added at com6.

Once I got the laptop to connect to my router, here’s what I did, step-by-step:

Step 1.
I Power-cycle the router and press Ctrl-Break within 60 seconds of the booting the router and put it into ROMMON.
Step 2.
I then type confreg 0x2142 at the rommon 1> prompt to boot from flash without loading the configuration. Then typed reset on the rommon 2> prompt to reboot the router without loading the saved configuration file.
Step 3.
I pressed Ctrl-C to skip the initial setup procedure.
Step 4.
Typed enable at the Router> prompt. This bring me in enable mode with the Router# prompt.
Step 5.
If I need the current config file, I would now have typed copy startup-config running-config to copy non-volatile RAM (NVRAM) into memory and change the password so I can keep the config and change only the password. However, as I only need to reset the password to something I know so I can play around this is router, I skipped this step.
Step 6.
I changed to configuration mode by typing config terminal at the Router# prompt.
Step 7.
On the Router(config)# prompt, I entered enable secret and changed my secret password to a my new password.
Step 8.
To make sure the new password will be loaded the next time I boot the router, I need to change the config register so the router will load the configuration with my new password on next reboot. In the Router(config)# prompt, I typed confreg 0x2102 to tell the router to boot from the saved config.
Step 9.
At this stage, I need to save the config, so I pressed Ctrl-Z and left config mode.
Step 10.
Finally, I am ready to save my config and issue a copy running-config startup-config.

I rebooted the router and was able to login with my new password!

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