C-3
Cisco 3700 Series Routers Hardware Installation Guide
OL-2180-08
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-register
value
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-register
command. 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-Z
to 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.
