Chapter 4 Troubleshooting the Installation
Performing Other Configuration Tasks
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Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
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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. The system then 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-grp through cisco17-grp or cisco2-prp through
cisco17-prp).
Configuration Register Settings
To change the software configuration register settings while running system
software, follow these steps:
Step 1 Enter the enable command and your password at the user EXEC mode prompt to
enter privileged EXEC mode:
Router> enable
Password: <password>
Router#
Step 2 Enter the configure terminal command at the privileged EXEC mode prompt on
the system console to enter global configuration mode, as shown in the following
example:
Router# configure terminal
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, as in the following:
Router(config)# config-register 0xvalue
Consult the hexadecimal column in Table 4-1 on page 4-2 for the possible settings
to enter as the four-bit value parameter.
Step 4 Exit global configuration mode by entering Ctrl-Z.
Router(config)# config-register 0xvalue
Router(config)# Ctrl-Z
Router#