Cisco 4500-M and Cisco 4700 ROM Monitor

This appendix describes the Cisco 4500-M and Cisco 4700 ROM monitor, the first software to run when the router is powered-up or reset. The Cisco 4500-M and Cisco 4700 ROM monitor supports more features than the familiar Cisco 4000-M ROM monitor. The ROM Monitor can help you isolate or rule out hardware problems encountered when installing your router. A summary of the ROM monitor diagnostic tests and command options is provided.

Entering the ROM Monitor Program

The ROM monitor diagnostics help initialize the processor hardware and boot the main operating system software. If you set the software configuration register (bits 3, 2, 1, and 0) to zero, you can start the router in the standalone ROM monitor. An example of the Cisco 4500-M and Cisco 4700 ROM monitor prompt follows:

rommon 1 >

To enable the Break key, and to default to booting at the ROM monitor while running the system software, reset the configuration register to 0x0 by entering configuration mode, and enter the configuration command following:

config-reg 0x0

The new configuration register value, 0x0, takes effect after the router is rebooted with the reload command. If you set the configuration to 0x0, you will have to manually boot the system from the console each time you reload the router.

Time Saver Break (system interrupt) is always enabled for 60 seconds after rebooting the system, regardless of whether break is configured to be off by setting the configuration register. During the 60-second window, you can break to the ROM monitor prompt.

Available ROM Monitor Commands

At the ROM monitor prompt, enter ? or help at the rommon 1 > prompt to display a list of available commands and options, as follows:

rommon 1 > ?
help                monitor builtin command help
boot                boot up an external process
dir                 list files in file system
dev                 list the device table
confreg             configuration register utility
reset               system reset
stack               produce a stack trace
context             display the context of a loaded image
frame               print out a selected stack frame
sysret              print out info from last system return
meminfo             main memory information
rommon 2 >

Note Further information about a command can be displayed by entering the command name with a -? option, which will cause the command usage message to be printed.

ROM Monitor Command Conventions

Following are ROM monitor command conventions:

Brackets [ ] denote an optional field. If a minus option is followed by a colon (for example: [-s:]) the user must provide an argument for the option.
A word in italics means that the user must fill in the appropriate information.
All of the built-in commands can be aborted (user interrupt signal) by pressing the <break> key at the console.

The following case-sensitive ROM monitor commands are among the most useful:

help--The help command prints a summary of the ROM monitor commands to the console screen.This is the same output as entering ?.
boot or b--Boot an image. The boot command with no arguments will boot the first image in boot flash. You can include an argument, filename, to specify a file to be booted over the network using the Trivial File Transfer Protocol (TFTP). The local device (see the description of b device following) can be specified by typing the device specifier (devid). If the specified device name is not recognized by the ROM monitor, the system will attempt to boot the image (imagename) from a network TFTP server. Do not insert a space between devid and imagename. Options to the boot command are -x, load image but do not execute, and -v, verbose. The form of the boot command follows:

boot [-xv] [devid][imagename] b--Boots the default system software from ROM b filename [host]--Boots using a network TFTP server. When a host is specified, either by name or IP address, the boot command will boot from that source. b flash:--Boots the first file in Flash memory

: b device:--Boots the first file found in the Flash device. The Flash device specified can be either flash:, to boot the Cisco Internetwork Operating System (Cisco IOS), or bootflash:, to boot the boot image in Flash.
: b device:name--An extension of the above command, allows you to specify a particular filename in the flash bank.

reset or i--Resets and initializes the system, similar to power-on.
dev--Lists boot device identifications on the router.

: For example:

rommon 10 > dev
Devices in device table:
        id  name
    flash:  flash 
bootflash:  boot flash 
    eprom:  eprom

dir--Lists the files on the named device, dir device, where the device is flash or bootflash; lists the available files on that device.

: For example:

rommon 11 > dir flash:
         File size           Checksum   File name
       2229799 bytes (0x220627)   0x469e    C4500-k

Debugging Commands

Most of the debugging commands are functional only when the Cisco IOS software has crashed or is aborted. If you enter the debug commands and Cisco IOS crash information is not available, the screen will display the following error message:

"xxx: kernel context state is invalid, can not proceed."

stack or k--Produces a stack trace.
context--Displays the processor context.
frame--Displays an individual stack frame.
sysret--Displays the return information from the last booted system image. This includes the reason for terminating the image, a stack dump of up to eight frames, and if an exception is involved, the address where the exception occurred.

: For example:

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

meminfo--Displays the size in bytes, the starting address, the available range of the main memory, the starting point and size of packet memory, and the size of nonvolatile memory (NVRAM).

rommon 9 > meminfo
 
Main memory size: 8 MB. Packet memory size: 4 MB
Available main memory starts at 0xa000e001, size 0x7f1fff
Packet memory starts at 0xa8000000
NVRAM size: 0x20000

Configuration Register

The configuration register resides in NVRAM. The configuration register is identical in operation to other Cisco routers. Enter confreg for the menu-driven system, or enter the new value of the register in hexadecimal.

Note The value is always interpreted as hex. The confreg utility will print a before and after view of the configuration register when used in menu-driven mode.

confreg [hexnum]--Executing the confreg command with the argument hexnum will change the virtual configuration register to match the hex number specified. Without the argument, confreg will dump the contents of the virtual configuration register in English and allow the user to alter the contents. The user is prompted to change or keep the information held in each bit of the virtual configuration register. In either case the new virtual configuration register value is written into NVRAM and does not take effect until the user resets or power cycles the platform.

: For example:

rommon 7 > confreg
 
     Configuration Summary
enabled are:
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]:  
enable  "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  [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

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