Datasheet

OL-17436-01

Additional Configuration and Maintenance Tasks

The following sections describes how to change the configuration register settings from EXEC mode and

from the ROM monitor mode:

• Commonly Used Configuration Register Value Settings

• Changing the Configuration Register Settings from EXEC Mode

• Changing the Configuration Register Settings from ROM Monitor Mode

Commonly Used Configuration Register Value Settings

To change the configuration register setting from normal operating mode, enter the config-register value

command. The most commonly used values are described in Table 23.

Table 23 Common config-register Settings

Note By default, the configuration register value is 0x2, which automatically boots the system to normal

EXEC mode.

Changing the Configuration Register Settings from EXEC Mode

To change the configuration register setting from normal operating mode, enter the config-register value

command.

Note To display the current configuration register setting, enter the show variables boot command in EXEC

mode.

Perform the following procedure in the order shown to restart the Router in ROM monitor mode:

SUMMARY STEPS

1. Connect a terminal to the primary RP console port and log in to the router.

2. configure

3. config-register value

4. commit

5. no config-register 0x0

6. commit

7. end

config-register Value Description

0x0 The router enters ROM monitor (rommon1>) on the next system boot.

0x2 The router boots the Cisco IOS XR software and default configuration on

the next system boot. After logging in, the user can access EXEC mode.

0x102 The router disables the break key.

0x42 The router enters the password recovery mode on the next system boot.