Cisco Systems 3700 Series Using the ROM Monitor, Entering ROM Monitor Mode, A P P E N D I X B

A P P E N D I X B

Using the ROM Monitor

This appendix describes the ROM monitor (also called the bootstrap program), the firmware that runs when your Cisco 3700 series router is powered up or reset. During normal operation, the ROM monitor helps to initialize the processor hardware and boot the operating system software. You can also use the ROM monitor to isolate or eliminate hardware problems and recover a corrupted Cisco IOS software image.

This appendix includes the following sections:

•Entering ROM Monitor Mode, page B-1

•ROM Monitor Commands, page B-2

•ROM Monitor Syntax Conventions, page B-3

•ROM Monitor Command Descriptions, page B-3

•Recovering Cisco IOS Software Images, page B-8

Entering ROM Monitor Mode

To use the ROM monitor, you must have access to the console port. See the “Connecting to a Console Terminal or Modem” section on page 3-22for information on connecting the console cable.

There are two ways of entering the ROM monitor mode:

•Use the reload command and the Break key to enter the ROM monitor mode for one-time use.

Break (system interrupt) is always enabled for 60 seconds after the router reboots, regardless of whether Break is configured on or off in the configuration register (see Appendix C, “Configuration Register”). During this 60-second period, you can break to the ROM monitor prompt by pressing the Break key.

Note If your console terminal does not have a Break key, see the terminal emulator documentation for instructions on generating a break (system interrupt).

•Set the configuration register so that the router enters the ROM monitor mode whenever it boots.

The new configuration register value, 0x0, is effective after the router is rebooted with the reload command. The router remains in the ROM monitor and does not boot the operating system.

As long as the configuration register value remains 0x0, you must manually boot the operating system from the console. See the boot command in the “ROM Monitor Command Descriptions” section on page B-3.

Cisco 3700 Series Routers Hardware Installation Guide

OL-2180-08 B-1