Cisco Systems Cisco 12008 manual Changing the Software Configuration Register Settings

Performing Other Configuration Tasks

Note If a bootable Cisco IOS software image exists in a Flash memory card inserted in PCMCIA slot 0 or slot 1, the software configuration register boot field setting is overridden and the system boots from the Cisco IOS software image in the Flash memory card, rather than from a network TFTP image (that is, from a computed filename in the range from cisco2-grpthrough cisco17-grp).

Changing the Software Configuration Register Settings

To change the software configuration register settings while running system software, perform the following steps:

Step 1 Enter the enable command and your password at the user EXEC mode prompt to establish the privileged EXEC mode:

Router> enable

Password:

Router#

Step 2 Enter the configure terminal command at the privileged EXEC mode prompt to establish the global configuration mode:

Router# conf t

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)#

Step 3 Set the contents of the software configuration register by entering the config- register value command at the global configuration mode prompt, where value is a hexadecimal number preceded by 0x.

Consult the hexadecimal column in Table 4-3 for the possible settings to enter as the 4-bit value parameter.

The config-registervalue command takes the following form:

Router(config)# config-register 0xvalue

Step 4 Exit the global configuration mode by entering Ctrl-Z:

Router(config)# config-register 0xvalue

Router(config)# Ctrl-Z

Router#

4-38Cisco 12008 Gigabit Switch Router Installation and Configuration Guide