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This appendix describes the ROM monitor (also called the bootstrap program), the firmware that runs when your Cisco 3600 series router is powered on or reset. The ROM monitor can help you isolate or rule out hardware problems encountered when installing your router.
This appendix contains the following sections:
In normal operation, the ROM monitor helps to initialize the processor hardware and boot the operating system software. To use the ROM monitor, you must have access to the console port. See the "Console Port" section.
From the operating system software, you can configure the router to remain in the ROM monitor the next time it boots by setting virtual configuration register bits 3, 2, 1, and 0 to zero. From the console, enter the following configuration command:
configuration-register 0x0
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.
If the configuration value remains 0x0, you must manually boot the operating system from the console. (See the boot command in the "Command Descriptions" section.)
 | TimeSaver 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 the appendix "Virtual Configuration Register"). During this 60-second period, you can break to the ROM monitor prompt by pressing the Break key. |
The ROM monitor prompt is as follows:
rommon 1 >
In this example, 1 (the number one) is the line number and is incremented at each prompt.
Enter ? or help at the ROM monitor prompt to display a list of available commands and options, as follows:
rommon 1 > ? alias set and display aliases command boot boot up an external process break set/show/clear the breakpoint confreg configuration register utility cont continue executing a downloaded image context display the context of a loaded image cookie display contents of cookie PROM in hex dev list the device table dir list files in file system dis disassemble instruction stream dnld serial download a program module frame print out a selected stack frame help monitor builtin command help history monitor command history iomemdef force the default IO memory configuration meminfo main memory information repeat repeat a monitor command reset system reset set display the monitor variables stack produce a stack trace sync write monitor environment to NVRAM sysret print out info from last system return unalias unset an alias unset unset a monitor variable xmodem x/ymodem image download rommon 2 >
Commands are case sensitive. You can abort any command by pressing the Break key at the console.
ROM monitor syntax in this appendix uses the following conventions:
This section lists some useful ROM monitor commands. Refer to the Cisco IOS configuration guides and command references for more information.
rommon 10 > dev Devices in device table: idname flash:flash slot0:PCMCIA slot 0 slot1:PCMCIA slot 1 eprom:eprom
rommon 11 > dir flash:
File size Checksum File name
2229799 bytes (0x220627) 0x469e C3600-j-m2
"xxx: kernel context state is invalid, can not proceed."
rommon 8 > sysret System Return Info: count: 19, reason: user break pc:0x60043754, error address: 0x0 Stack Trace: FP: 0x80007e78, PC: 0x60043754 FP: 0x80007ed8, PC: 0x6001540c FP: 0x80007ef8, PC: 0x600087f0 FP: 0x80007f18, PC: 0x80008734
rommon 9 > meminfo Main memory size: 16 MB in 32-bit mode. Available main memory starts at 0xa000e000, size 16328KB IO (packet) memory size: 25 percent of main memory. NVRAM size: 128KB
The virtual configuration register resides in NVRAM. You can display or modify the virtual configuration register from either the ROM monitor or the operating system software. For procedures used to change the virtual configuration register from the operating system, and for information about register settings, see Appendix D, "Virtual Configuration Register."
To change the virtual configuration register from the ROM monitor, enter confreg by itself to access the menu mode, or enter the new value of the register in hexadecimal.
rommon 7 > confreg
Configuration Summary
enabled are:
break/abort has effect
console baud: 9600
boot: the ROM Monitor
do you wish to change the configuration? y/n [n]: y
enable "diagnostic mode"? y/n [n]: y
enable "use net in IP bcast address"? y/n [n]:
enable "load rom after netboot fails"? y/n [n]:
enable "use all zero broadcast"? y/n [n]:
disable "break/abort has effect"? y/n [n]:
enable "ignore system config info"? y/n [n]:
change console baud rate? y/n [n]: y
enter rate: 0 = 9600,1 = 4800,2 = 1200,3 = 2400
4 = 19200, 5 = 38400, 6 = 57600, 7 = 115200[0]: 0
change the boot characteristics? y/n [n]: y
enter to boot:
0 = ROM Monitor
1 = the boot helper image
2-15 = boot system
[0]: 0
Configuration Summary
enabled are:
diagnostic mode
console baud: 9600
boot: the ROM Monitor
do you wish to change the configuration? y/n [n]:
You must reset or power cycle for new config to take effect
The BOOTLDR environment variable is used to change the default boothelper image from the first image in Flash memory to the specified image.
To set the BOOTLDR environment variable, perform the following tasks, beginning in the privileged EXEC mode.
First, verify that Flash memory contains the boot image:
Router> show [/all | /deleted] | [/long] [device:][filename]
Enter configuration mode:
Router> configure terminal
Set the BOOTLDR environment variable to specify the Flash device and filename of the boot image:
Router> boot bootldr device:filename
Exit configuration mode:
Router> Ctrl-Z
Save the BOOTLDR environment variable to your startup configuration:
Router> copy running-config startup-config
You can verify the contents of the BOOTLDR environment variable by using the show boot command:
Router> show boot
The xmodem command establishes a connection between a console and the router console or auxiliary port for disaster recovery if both the boot and system images are erased from Flash memory. For a description of the disaster recovery procedure, see the "Recovering Software Images" section.
Other options are:
This section describes how to recover a lost enable password.
Follow this procedure to recover a lost enable password:
Step 1 Connect an ASCII terminal or a PC running a terminal emulation program to the console port located on the front panel of the router. See the "Console Port" section.
Step 2 Reboot the router. If asked whether you would like to enter the initial dialog, answer n:
Would you like to enter the initial dialog? [yes]: n
You are now in the router's normal operating mode.
Step 3 After a few seconds you see the user EXEC prompt (Router>). Enter the show version command to display the existing configuration register value. Record the setting of the configuration register.
Step 4 If Break is enabled, send a Break by pressing the Break key. This action causes the terminal to display the ROM monitor prompt (rommon >). Proceed to Step 6.
Step 5 If Break is disabled, or if you do not know whether Break is enabled, or sending a Break fails, power OFF the router, wait five seconds, and power it ON again. Within five seconds of powering on the router, press the Break key. This action causes the terminal to display the ROM monitor prompt (rommon >).
Step 6 Enter confreg at the ROM monitor prompt. This command allows you to configure the register.
rommon> confreg
Step 7 Enter y at the following prompt:
Do you wish to change the configuration? y/n [n]: y
Step 8 Enter n in response to all the prompts until you reach the following prompt, then enter y:
enable "ignore system config info"? [y/n] n: y
Step 9 Enter n in response to all the prompts until you reach the following prompt, then enter y:
change the boot characteristics? [y/n] [n]: y
Step 10 At the following prompt, enter 2 and press Return. A configuration summary is displayed.
enter to boot: 2
Step 11 Enter n at the following prompt:
Do you wish to change the configuration? y/n [n]: n
Step 12 Enter reset at the ROM monitor prompt. The router reboots.
rommon> reset
Step 13 Enter n at the following prompt:
Would you like to enter the initial dialog? [yes]: no
Step 14 Enter enable to enter privileged EXEC mode:
Router> enable Password: <password> Router#
Configuration changes can be made only in enable mode. The prompt changes to the privileged EXEC prompt (Router#):
Step 15 Enter the show startup-config command to display the enable password in the configuration file:
Router# show startup-config
Step 16 Enter the configure terminal command to enter configuration mode:
Router# configure terminal
Step 17 Enter the configure register command followed by a number to return the original value found in Step 3.
Step 18 Press Ctrl-z to exit configuration mode.
Step 19 Reboot the router and enter the recovered password.
If both the boot and system images have been erased and only the ROM monitor is available, you can use the ROM monitor xmodem command to copy a Cisco IOS image to Flash memory from the console. The console can be connected directly to the router through the console port, or remotely through a modem connected to the auxiliary port.
The console must have the following files to use this procedure:
Perform the following steps to copy the Cisco IOS image to Flash memory:
Step 1 Connect the console using the instructions in the "Connecting the Console Terminal and Modem" section.
Step 2 Power ON the router. The power-on self-test diagnostics run and the boot ROM searches for a valid boot image and Cisco IOS image in Flash memory. If the boot image and Cisco IOS image are not found, the ROM monitor prompt is displayed:
rommon 1>
Step 3 Enter the xmodem command and the name of the source file containing the Cisco IOS image:
rommon 1> xmodem filename
Step 4 The source file is searched for and found. Messages similar to the following appear:
Do not start upload program yet... File size Checksum File name 2537948 bytes (0x26b9dc) 3640-boot-l WARN: This operation will ERASE bootflash. If the xmodem download to bootflash fails, you will lose any good image you may already have in bootflash. Invoke this application only for disaster recovery. Do you wish to continue? [yes/no]:
Step 5 Enter yes to copy the Cisco IOS image into Flash memory. Messages similar to the following appear:
Ready to receive file prog ... Erasing flash at 0x3000000 program flash location 0x3000000 Transfer complete!
Posted: Thu Jul 29 08:09:13 PDT 1999
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