Cisco Systems 3700 Series manual Configuring the Boot Field

Appendix C Configuration Register

Configuring the Boot Field

Step 5 After a few seconds, you see the user EXEC prompt (Router>). Enter the enable command and your password to enter privileged EXEC mode:

Router> enable

Password: password

Router#

Step 6 At the privileged EXEC prompt (Router#), enter the configure terminal command:

Router# configure terminal

Enter configuration commands, one per line.

Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z

Step 7 Enter the config-registervalue command, where value is a hexadecimal number preceded by 0x (see Table C-2), to set the contents of the configuration register:

Router(config)# config-register 0x value

Note Cisco IOS software does not allow you to change the console speed bits directly with the

config-registercommand. To change the console speed, complete this sequence:

Router# configure terminal

Router(config)# line console 0

Router(config-line)# speed 9600

Step 8 Press Ctrl-Zto exit configuration mode.

Step 9 Copy the new console speed to NVRAM:

Router# copy run start

The new settings are saved to NVRAM, but they are not effective until the router restarts; for example, when you switch the power off and on or when you enter a reload command from the console.

Step 10 Enter the show version command to display the configuration register value currently in effect and the value that will be used at the next reload. The value is shown on the last line of the display:

Configuration register is 0x142 (will be 0x142 at next reload)

Step 11 Reboot the router. The new value is effective after the router reboots.

Configuring the Boot Field

The lowest four bits of the configuration register (bits 3, 2, 1, and 0) form the boot field. (See Table C-2.)

Table C-2	Explanation of Boot Field Configuration Register Bits (00 to 03)
Boot Field		Meaning
00		Stays at the ROM monitor on a reload or power cycle.
01		Boots the first image in CompactFlash memory as a system image.
02-F		Enables default booting from CompactFlash memory.
		Enables boot system commands that override default booting from CompactFlash
		memory.

Cisco 3700 Series Routers Hardware Installation Guide

OL-2180-08 C-3