Configuration Register; Changing The Configuration Register Manually; Changing The Configuration Register Using Prompts - Cisco CISCO851-K9 - 851 Integrated Services Router Configuration Manual

Configuration Register

You will see output similar to the following:
IP_ADDRESS: 10.3.6.7
IP_SUBNET_MASK: 255.255.0.0
DEFAULT_GATEWAY: 10.3.0.1
TFTP_SERVER: 192.168.254.254
TFTP_FILE: c870-advsecurityk9-mz
Do you wish to continue? y/n:
If you are sure that you want to continue, enter y in response to the question in the output:
Step 3
Do you wish to continue? y/n:
The router begins to download the new file.
If you mistakenly entered yes, you can enter Ctrl-C or Break to stop the transfer before the flash
memory is erased.
Configuration Register
The virtual configuration register is in nonvolatile RAM (NVRAM) and has the same functionality as
other Cisco routers. You can view or modify the virtual configuration register from either the ROM
monitor or the operating system software. Within the ROM monitor, you can change the configuration
register by entering the register value in hexadecimal format, or by allowing the ROM monitor to prompt
you for the setting of each bit.

Changing the Configuration Register Manually

To change the virtual configuration register from the ROM monitor manually, enter the confreg
command followed by the new value of the register in hexadecimal format, as shown in the following
example:
rommon 1 > confreg 0x2101
You must reset or power cycle for new config to take effect
rommon 2 >
The value is always interpreted as hexadecimal. The new virtual configuration register value is written
into NVRAM but does not take effect until you reset or reboot the router.

Changing the Configuration Register Using Prompts

Entering the confreg command without an argument displays the contents of the virtual configuration
register and a prompt to alter the contents by describing the meaning of each bit.
In either case, the new virtual configuration register value is written into NVRAM but does not take
effect until you reset or reboot the router.
Cisco 850 Series and Cisco 870 Series Access Routers Software Configuration Guide
C-6
[n]:
[n]:y
Appendix C ROM Monitor
OL-5332-01