Factory reset a Cisco 1841 router

To reset a 1841, you’ll need to connect to the console and put the router in ‘rommon’ mode

• Connect up your console cable and get PuTTY ready on the correct port.
• Power on the router. As soon as you see iOS loading in PuTTY, right click the top of the PuTTY window and go to Special Commands > Break.
  
• The router should now be in rommon mode. Run the following command, then reboot the router with ‘reset’:
  

  confreg 0x2142

  

• Once the router has been rebooted, save the config with:

  copy running-config startup-config