Connect a PC with a terminal emulation software to the console port on the Cisco router. Cisco 2620 router, IOS 12.2. Settings for the terminal
9600 baud rate
No parity
8 data bits
1 stop bit
No flow control
Turn off the router, then back on. After the router is on press the BREAK key(Alt + b on Tera Term) within 60 seconds of start to have the router in ROMMON. The prompt will show.
rommon 1>
Then type confreg 0x2142 to boot from flash (this will bypass startup configuration).
rommon 1>confreg 0×2142
Type reset at the prompt (ignores saved configuration, then reboots).
rommon 2>reset
Press Ctrl-c to skip the initial procedure. Type enable at the prompt.
Router>enable
Then the prompt changes to Router#. Now type.
Router#configure memory
or
Router#copy startup-config running-config
commands will copy NVRAM in to memory. To show the current configuration on the router use.
Router#show running-config
The output will be : enable passwords enable secret vty console password which will be in encrypted or unencrypted format, encrypted passwords should be change to a new one. To change encrypted or enable secret password do the following.
Router#
Router#configure terminal
Router(config)#enable secret Router(config)#exit
Issue the no shutdown command on every interface.
Router#
Router(config)#interface serial 0/1
Router(config-t)#no shutdown
Router(config-t)#exit
Type config-register use the value 0×2102.
Router(config)#config-register 0×2102
Press Ctrl-z to leave configuration mode.
Router#
Type write memory or copy running-config startup-config to commit all of the new changes and configurations.