Cisco 7000 Hardware Installation And Maintenance page 179

Table 5-5 Explanation of Boot Field (Configuration Register Bits 00 to 03)
Boot Field Meaning
00 Stays at the system bootstrap prompt
01 Boots system image in system ROM
02 to 0F Specifies a default netboot filename
Enables boot system commands that override the default netboot filename
Changing Settings
Some common reasons to modify the value of the software configuration register are as follows:
•
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 router 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 router finds no boot system commands, it uses the
configuration register value to form a filename from which to netboot a default system image
stored on a network server. (See Table 5-6.)
To change the configuration register while running the system software, follow these steps:
Enter the enable command and your password to enter privileged level, as follows:
Step 1
Router> enable
Password:
router#
At the privileged-level system prompt (router #), enter the command configure terminal.
Step 2
You will be prompted as shown in the following example:
Router# conf term
Enter configuration commands, one per line. End with CTRL/Z.
Step 3 To set the contents of the configuration register, enter the config-register value
configuration command where value is a hexadecimal number preceded by 0x
(see Table 5-4), as in the following:
config-register 0xvalue
Exit the configuration mode by entering Ctrl-Z. The new value settings will be saved to
Step 4
memory; however, the new settings do not take effect until the system software is reloaded
by rebooting the router.
Installing and Configuring Processor Modules
Maintenance 5-175