User guide

B-18 Cisco 2500 Series Access Server User Guide
Virtual Configuration Register Settings
Changing Configuration Register Settings
You might want to modify the value of the virtual configuration register for the following
reasons:
• Recover a lost password.
• Change the console baud rate.
• Enable or disable Break.
• Allow you to manually boot the operating system using the b command at the bootstrap
program (ROM monitor) prompt.
• Force the access server to boot automatically from the system bootstrap software (boot
ROM image) or from its system image in Flash memory, and read any boot system
commands that are stored in the configuration file in NVRAM. If the access server finds
no boot system commands, it uses the configuration register value to form a filename
from which to boot a default system image stored on a network server.
To change the configuration register while running the system software, take the following
steps:
Step 1 Enter the enable command and your password to enter privileged mode:
router> enable
Password:
router#
1. The factory default value for the configuration register is 0x2102. This value is a combination of the
following: bit 13 = 0x2000, bit 8 = 0x0100, and bits 00 through 03 = 0x0002.
11–12 0x0800–0x1000 Console line speed
13 0x2000 Load the boot ROM software if a Flash boot fails five times
14 0x4000 IP broadcasts do not have network numbers
15 0x8000 Enable diagnostic messages and ignore the contents of
NVRAM
Bit No.
1
Hexadecimal Meaning