Cisco 2600 Series Routers Hardware Installation Guide - Using the ROM Monitor [Cisco 2600 Series Multiservice Platforms]

Table Of Contents

Using the ROM Monitor

Entering ROM Monitor Mode

ROM Monitor Commands

ROM Monitor Command Syntax Conventions

ROM Monitor Command Descriptions

Router Management Commands

Boot Commands in the ROM Monitor

Informational Commands in the ROM Monitor

Other Useful ROM Monitor Commands

Debugging Commands

Configuration Register Commands

Recovering Cisco IOS Software Images

Copying an Image from the Console Using the xmodem Command

Description and Options of the xmodem Command

Console Requirements

Procedure for the xmodem Command

Copying an Image from a TFTP Server Using the tftpdnld Command

Restrictions on the tftpdnld Command

Procedure for the tftpdnld Command

Using the ROM Monitor

This appendix describes the use of the ROM monitor (also called the bootstrap program), which is the firmware that runs when you power up or restart a Cisco router. 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:

•Help isolate hardware problems encountered when installing your router.

•Download a new Cisco IOS image if the operating image is corrupted.

This appendix contains the following sections:

•Entering ROM Monitor Mode

•ROM Monitor Commands

•ROM Monitor Command Syntax Conventions

•ROM Monitor Command Descriptions

•Recovering Cisco IOS Software Images

Entering ROM Monitor Mode

To use the ROM monitor, you must have access to the console port. Refer to the "Connecting to a Console Terminal or Modem" section on page 3-20 for 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, refer to 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. Refer to the boot command in the "ROM Monitor Command Descriptions" section.

The two methods of entering the ROM monitor mode are as follows:

Enter ROM Monitor Mode by Using the reload Command

Connect to the router from a console, and follow these steps:

Step 1 Restart the router with the reload command.
Router# reload
Step 2 Press the Break key during the first 60 seconds of the system booting.

This forces the router into ROM monitor mode, and the ROM monitor prompt is displayed:

rommon 1>

Enter ROM Monitor Mode by Resetting the Configuration Register

Connect to the router from a console, and follow these steps:

Step 1 Set the bits 3, 2, 1, and 0 of the configuration register to zero:
Router# configuration-register 0x0
Step 2 Restart the router with the reload command:

The router boots into the ROM monitor mode, and the ROM monitor prompt is displayed:

rommon 1>

Note The number that appears in the ROM monitor prompt (1>, 2>, and so forth) is the line number. It increments each time you enter a ROM monitor command.

ROM Monitor Commands

Showing ROM Monitor Commands

Enter ? or help at the ROM monitor prompt to see a list of available commands. For example:
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 the file system
dis         display 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      set IO mem to a default 25%
meminfo     main memory information
repeat      repeat a monitor command
reset       system reset
rommon-pref   select ROMMON
set         display the monitor variables
stack       produce a stack trace
sync        write monitor environment to NVRAM
sysret      print out info from last system return
tftpdnld    tftp image download
unalias     unset an alias
unset       unset a monitor variable
xmodem      x/ymodem image download
rommon 2>
Note Not all ROM monitor commands are available on all platforms.

Displaying Information About ROM Monitor Command Syntax

To display information about command syntax, enter the command name followed by -?.

Entering ROM Monitor Commands

ROM monitor commands are case-sensitive. Enter commands exactly as shown.

Interrupting ROM Monitor Commands

You can end any command by generating a Break (system interrupt) at the console.

ROM Monitor Command Syntax Conventions

The ROM monitor syntax in this appendix uses the following conventions:

•Square brackets [ ] denote an optional element. In the following example, the element abc is not required, but you can specify it if you choose:

command [abc]

•If a minus option is followed by a colon (for example, [-s:]) you must provide an argument for the option.

•A term in italics means that you must fill in the appropriate information. In the following example, you replace the term in italics with the interface type you are using:

command interface-type

ROM Monitor Command Descriptions

Router Management Commands

This section lists some useful ROM monitor commands. Refer to the Cisco IOS configuration guides and command references for more information on ROM monitor commands.

Boot Commands in the ROM Monitor

Functions of Boot Commands

The router always boots first from a Cisco IOS image in flash memory, because there is no separate, dedicated boothelper image ([rx]boot). The first image in flash memory functions as the boothelper image, but you can override this by setting the BOOTLDR Monitor environment variable to point to another image. If the ROM monitor does not recognize a device ID specified in the boot command (device does not exist, or command entered incorrectly), the router boots from the first image in flash memory.

To boot a router from a Cisco IOS image on a TFTP server (netboot), the installed DRAM must be adequate to hold two uncompressed Cisco IOS images: the image from flash memory and the image downloaded from the TFTP server.

If the router is configured to boot from a TFTP server (boot bits in the configuration register are set from 2 to 15), the router first boots from the image in flash memory. It decompresses that image in DRAM, parses the boot system commands, downloads the Cisco IOS image from the TFTP server, and decompresses it in DRAM. After the Cisco IOS image from the TFTP server is in DRAM, the DRAM memory occupied by the boothelper image is released.

Note Booting from a TFTP server is useful if the router does not have enough flash memory to hold large images. With a small image in flash memory (just large enough to support the necessary interfaces), the router boots from flash memory, and then the larger image is downloaded from the TFTP server.

Entering Boot Commands

The boot command syntax is as follows, where:

•partition is a partition number in the flash memory.

•filename is the Cisco IOS image filename.

•tftpserver is the IP address of the TFTP server.

•-x directs the router to load the image but not execute the boot process.

•-v (verbose) specifies that progress print setting messages and error information be displayed.

boot [flash: [partition: [filename]] | slot0: [partition: [filename]] | slot1: [partition: [filename]] | filename tftpserver] [-x] [-v]

Some examples of boot commands are as follows:

Note In all boot commands, boot can be entered as b.

•boot—Boots from the first Cisco IOS image in internal flash memory.

•boot flash:—Boots from the first Cisco IOS image in the internal Flash memory.

•boot flash: partition:—Boots from the first Cisco IOS image in the specified partition in internal flash memory.

•boot flash: filename—Boots from the Cisco specified IOS image in internal flash memory.

•boot flash: partition: filename—Boots from the specified Cisco IOS image in the specified partition in internal flash memory.

•boot slot0:—(Cisco 2691 only) Boots from the first Cisco IOS image in the first partition in flash memory in slot 0.

•boot slot0:2:—(Cisco 2691 only) Boots from the first Cisco IOS image in the second partition in compact flash memory in slot 0.

•boot slot0: filename—(Cisco 2691 only) Boots from the specified Cisco IOS image in compact flash memory in slot 0.

•boot slot1:3: filename—(Cisco 2691 only) Boots from the specified Cisco IOS image in the third partition in compact flash memory in slot 1.

•boot filename tftpserver— Boots from the specified Cisco IOS image on the specified TFTP server (after first booting from flash). For example:

boot c2600-i-mz 172.15.19.11

Note Use the CLI commands show version and show hardware to see the source of the currently running Cisco IOS image.

Informational Commands in the ROM Monitor

dev—(Cisco 2691 only) Lists boot device identifications on the router, for example:
rommon 2 > dev
Devices in device table:
        id  name
    flash:  internal compact flash
    slot0:  external compact flash
    eprom:  eprom 
rommon 3 > 
dir device:[partition:]—Lists the files on the named device. For example:
rommon 8> dir flash:
         File size               Checksum   File name
       2229799 bytes (0x220627)   0x469e    C2600-j-m2.113-4T
help—Shows a summary of ROM monitor commands (equivalent to ?).

meminfo—Displays main memory size, starting address, and available range; size of packet memory; and size of NVRAM. The following example shows the meminfo command:
rommon 9> meminfo
Main memory size: 32 MB.
Available main memory starts at 0xa000e000, size 32704KB
IO (packet) memory size: 25 percent of main memory.
NVRAM size: 32KB
meminfo [-l]—The meminfo command with the -l option shows supported DRAM configurations. The following example shows an example of the meminfo -l command:
rommon 10> meminfo -l
Supported memory configurations:
DIMM 0       DIMM 1
-------------------
             4M
             8M-DUAL
             16M
              32M-DUAL
4M
4M           4M
4M           8M-DUAL
4M           16M
4M           32M-DUAL
8M-DUAL
8M-DUAL      4M
8M-DUAL      8M-DUAL
8M-DUAL      16M
8M-DUAL      32M-DUAL
16M
16M          4M
16M          8M-DUAL
16M          16M
16M          32M-DUAL
32M-DUAL
32M-DUAL     4M
32M-DUAL     8M-DUAL
32M-DUAL     16M
32M-DUAL     32M-DUAL
Other Useful ROM Monitor Commands

reset or i—Resets and initializes the router, similar to power on.

tftpdnld—(Except Cisco 2691) Downloads an image using TFTP from a remote server. See the "Copying an Image from a TFTP Server Using the tftpdnld Command" procedure.

Debugging Commands

Most debugging commands are functional only when Cisco IOS software has crashed or failed to initialize (boot). Debugging commands should normally be entered only under the direction of a Cisco engineer. If you enter a debugging command and Cisco IOS crash information is not available, the following error message appears:
"xxx: kernel context state is invalid, cannot proceed."
The following ROM monitor debugging commands provide information about software failures:

•stack or k—Produces a stack trace.

•context—Views processor context.

•frame—Views an individual stack frame.

•sysret—Views return information from the last booted system image. This information 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: a SegV exception
pc:0x802b1040,  error address: 0x802b1040
Stack Trace:
FP: 0x80908398, PC: 0x802b102c
FP: 0x809083b0, PC: 0x802b0b88
FP: 0x809083d8, PC: 0x8017039c
FP: 0x809083e8, PC: 0x8016f764
Configuration Register Commands

The configuration register resides in NVRAM. You can view or modify the configuration register from either the ROM monitor or the operating system software.

For procedures used to change the configuration register from the operating system, and for information about configuration register settings, see Appendix C, "Configuration Register."

To modify the configuration register from the ROM monitor, you can:

•Enter the confreg command by itself for menu mode. See the "Modifying the Configuration Register in Menu Mode" section below.

•Enter the confreg command plus the new hexidecimal value of the configuration register. See the "Modifying the Configuration Register by Hexidecimal Entry" section.

In either case, the new configuration register value is written into NVRAM, but is not effective until you reboot (using the ROM monitor reset command) or power cycle the router.

Modifying the Configuration Register in Menu Mode

Entering the confreg command without an argument displays the contents of the configuration register, and prompts you to alter the contents by describing the meaning of each bit.

The following display shows an example of the confreg command:
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
break/abort has effect
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
Modifying the Configuration Register by Hexidecimal Entry

Entering the confreg command plus a hexidecimal value changes the contents of the configuration register. The syntax is confreg [hexnum]; values entered are always interpreted as hexadecimal. The following example changes the value of the configuration register to the factory default:
rommon 7> confreg 0x2102
You must reset or power cycle the router for new configuration to take effect.

Recovering Cisco IOS Software Images

If your Cisco router experiences difficulties and no longer contains a valid Cisco IOS software image in flash memory, you can download a new Cisco IOS image using one of the following ROM monitor commands:

•xmodem—(All Cisco 2600 series routers) Use this command to copy a Cisco IOS image from the console, if the computer attached to your console has a terminal emulator with Xmodem capability. See the "Copying an Image from the Console Using the xmodem Command" procedure.

Note Downloading a Cisco IOS image from a console is very slow. This procedure should be used only in an emergency and is not recommended for normal Cisco IOS image upgrades.

For the fastest possible download from a console, set the console speed to 115200 bps by using the confreg ROM monitor command. See the "Configuration Register Commands" procedure.

•tftpdnld—(Except Cisco 2691) Use this command to copy a Cisco IOS image from a TFTP server that is accessible through the FastEthernet 0/0, Ethernet 0/0, or Token Ring 0/0 port. See the "Copying an Image from a TFTP Server Using the tftpdnld Command" procedure.

Note The tftpdnld command is not available on the Cisco 2691 router. The recommended method for installing a Cisco IOS image on a Cisco 2691 router is from a CompactFlash memory card loaded in the external CompactFlash memory card slot. See the "Entering Boot Commands" procedure.

Copying an Image from the Console Using the xmodem Command

Description and Options of the xmodem Command

The xmodem command establishes a connection between a console and the router console port for disaster recovery, if both the boot and system images are erased from flash memory.

xmodem [filename]—Establishes an Xmodem connection between the console and the router. The optional argument filename specifies the source file containing the Cisco IOS image.

Other options include the following:

•c—Use cyclic redundancy check (CRC-16).

•y—Use Ymodem transfer protocol.

•r—Copy the image to dynamic random-access memory (DRAM) for launch.

•x—Do not launch image on completion of download.

Console Requirements

The console computer (PC) must have the following files to use this procedure:

•Terminal emulation application program supporting one of the following file transfer protocols:

–Xmodem

–Xmodem-CRC

–Xmodem-1K

–Ymodem

•Cisco IOS image file

Procedure for the xmodem Command

To copy a Cisco IOS image from a console to flash memory, perform the following procedure.

Note File transfer from a console is slow and will take many minutes.

Step 1 Connect a console to the router's console port using the instructions in the "Connecting to a Console Terminal or Modem" section on page 3-20.

Step 2 Power up 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
When the source file is found, messages similar to the following appear:
Do not start upload program yet...
File size           Checksum   File name
2537948 bytes       (0x26b9dc) c2600-i-mz.122-10.bin
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 4 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!
The router is now ready to boot from the Cisco IOS image. Enter the reset ROM monitor command to reboot the router.

Note If you have set the console speed to 115200, you may want to reset it to the previous speed or to the factory default speed (typically 9600 bps). See the "Configuration Register Commands" procedure.

Copying an Image from a TFTP Server Using the tftpdnld Command

The tftpdnld command downloads a Cisco IOS software image from a remote server accessible from a FastEthernet, Ethernet, or Token Ring network interface on a Cisco 2600 series router (except Cisco 2691). The tftpdnld command downloads the Cisco IOS software image into flash memory using TFTP.

Restrictions on the tftpdnld Command

The following software restrictions apply when using the tftpdnld command:

•Ethernet and FastEthernet—Accepts and sends only Ethernet V2.0 data packets.

•Token Ring—Accepts and sends only Token Ring frames with IEEE802.3 SNAP frames. Does not support any frames with routing information fields (RIFs), limiting all use of the tftpdnld command to a TFTP server on the local ring. If the TFTP server resides off the local ring, you must establish a path to the server through a router or transparent bridge from the local ring.

Procedure for the tftpdnld Command

Step 1 Specify the required variables, for example:
rommon 1> IP_ADDRESS=172.15.19.11
rommon 2> IP_SUBNET_MASK=255.255.255.0
rommon 3> DEFAULT_GATEWAY=172.16.19.1
rommon 4> TFTP_SERVER=172.15.20.10
rommon 5> TFTP_FILE=/tftpboot/c2600-i-mz
The syntax for specifying the variables is:
VARIABLE_NAME=value
The variables that you must specify include the following:

•IP_ADDRESS—IP address for the router you are using.

•IP_SUBNET_MASK—Subnet mask for the router you are using.

•DEFAULT_GATEWAY—Default gateway for the router you are using (not required if the TFTP server is in the same subnet as the router).

•TFTP_SERVER—IP address of the server from which you want to download the image file.

•TFTP_FILE—Name of the file that you want to download.

The following tftpdnld command variables are optional:

•TFTP_VERBOSE—Print setting. The default is 1.

–0=quiet—After you enter the tftpdnld command, the prompt

Do you wish to continue? y/n:

is the only information that appears until the command completes successfully or fails.

–1=progress—Displays the state of the required tftpdnld command variables. Also displays progress characters to indicate successful and lost packet transmissions.

–2=verbose—Displays all progress print setting messages, along with error information. The information provided by this print setting may be useful when debugging interface link and configuration problems that may prevent connecting to the TFTP server.

•TFTP_RETRY_COUNT—Number of times from 1 to 65535 that the ROM monitor will retry address resolution protocol (ARP) and acknowledge (ACK). The default is 7 retries.

•TFTP_TIMEOUT—Overall timeout of the download operation in seconds. The range is from 1 to 65535 seconds. The default is 7200 seconds.

•TFTP_CHECKSUM—Performs a checksum test on the image. 0=checksum off, 1=checksum on. The default is 1.

•FE_SPEED_MODE—Sets the Fast Ethernet speed and duplex mode. 0=10 Mbps half-duplex mode, 1=10 Mbps full-duplex mode, 2=100 Mbps half-duplex mode, 3=100 Mbps full-duplex mode, and 4=auto-negotiation. The default is 4.

Note Specify the FE_SPEED_MODE variable only for routers with a Fast Ethernet network interface.

•TR_SPEED_MODE—Sets the Token Ring speed and duplex mode. 0=4 Mbps half-duplex mode, 1=4 Mbps full-duplex mode, 2=16 Mbps half-duplex mode, and 3=16 Mbps full-duplex mode. The default is 2.

Note Specify the TR_SPEED_MODE variable only for routers with a Token Ring network interface; or for routers with both an Ethernet and a Token Ring port, those routers that are set to use the Token Ring port with the tftpdnld command.

•TR_1E1R_PORT—Sets the port to be used with the tftpdnld command. 0=Use Ethernet port; 1=Use Token Ring port. The default is 0.

Note Specify the TR_1E1R_PORT variable only for those routers with both an Ethernet and a Token Ring port.

Step 2 Enter the tftpdnld [-h] [-r] command:

Options include the following:

•h—Displays the tftpdnld command help screen.

•r—Loads the Cisco IOS software image only to DRAM and launches the image without writing the image into flash memory.
rommon 6> tftpdnld
     IP_ADDRESS=172.15.19.11
     IP_SUBNET_MASK=255.255.255.0
     DEFAULT_GATEWAY=172.16.19.1
     TFTP_SERVER=172.15.20.10
     TFTP_FILE=/tftpboot/2600-i-mz
Invoke this command for disaster recovery only.
WARNING: all existing data in all partitions on flash will be lost!
Do you wish to continue? y/n: [n]:
Step 3 Enter y to download the Cisco IOS software image. When the process is complete, the ROM monitor mode prompt appears on your screen.
rommon 7>
The router is now ready to boot from the Cisco IOS image. Enter the boot ROM monitor command to reboot the router.

	Cisco 2600 Series Routers Hardware Installation Guide
	Using the ROM Monitor
Cisco 2600 Series Routers Hardware Installation Guide Preface Overview of Cisco 2600 Series Routers Preparing to Install the Router Installing the Router Troubleshooting Using the ROM Monitor Configuration Register Index	Download this chapter Using the ROM Monitor Download the complete book Cisco 2600 Routers Hardware Installation Guide (PDF - 3 MB) Feedback Table Of Contents Using the ROM Monitor Entering ROM Monitor Mode ROM Monitor Commands ROM Monitor Command Syntax Conventions ROM Monitor Command Descriptions Router Management Commands Boot Commands in the ROM Monitor Informational Commands in the ROM Monitor Other Useful ROM Monitor Commands Debugging Commands Configuration Register Commands Recovering Cisco IOS Software Images Copying an Image from the Console Using the xmodem Command Description and Options of the xmodem Command Console Requirements Procedure for the xmodem Command Copying an Image from a TFTP Server Using the tftpdnld Command Restrictions on the tftpdnld Command Procedure for the tftpdnld Command Using the ROM Monitor This appendix describes the use of the ROM monitor (also called the bootstrap program), which is the firmware that runs when you power up or restart a Cisco router. 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: •Help isolate hardware problems encountered when installing your router. •Download a new Cisco IOS image if the operating image is corrupted. This appendix contains the following sections: •Entering ROM Monitor Mode •ROM Monitor Commands •ROM Monitor Command Syntax Conventions •ROM Monitor Command Descriptions •Recovering Cisco IOS Software Images Entering ROM Monitor Mode To use the ROM monitor, you must have access to the console port. Refer to the "Connecting to a Console Terminal or Modem" section on page 3-20 for 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, refer to 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. Refer to the boot command in the "ROM Monitor Command Descriptions" section. The two methods of entering the ROM monitor mode are as follows: Enter ROM Monitor Mode by Using the reload Command Connect to the router from a console, and follow these steps: Step 1 Restart the router with the reload command. Router# reload Step 2 Press the Break key during the first 60 seconds of the system booting. This forces the router into ROM monitor mode, and the ROM monitor prompt is displayed: rommon 1> Enter ROM Monitor Mode by Resetting the Configuration Register Connect to the router from a console, and follow these steps: Step 1 Set the bits 3, 2, 1, and 0 of the configuration register to zero: Router# configuration-register 0x0 Step 2 Restart the router with the reload command: The router boots into the ROM monitor mode, and the ROM monitor prompt is displayed: rommon 1> Note The number that appears in the ROM monitor prompt (1>, 2>, and so forth) is the line number. It increments each time you enter a ROM monitor command. ROM Monitor Commands Showing ROM Monitor Commands Enter ? or help at the ROM monitor prompt to see a list of available commands. For example: 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 the file system dis display 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 set IO mem to a default 25% meminfo main memory information repeat repeat a monitor command reset system reset rommon-pref select ROMMON set display the monitor variables stack produce a stack trace sync write monitor environment to NVRAM sysret print out info from last system return tftpdnld tftp image download unalias unset an alias unset unset a monitor variable xmodem x/ymodem image download rommon 2> Note Not all ROM monitor commands are available on all platforms. Displaying Information About ROM Monitor Command Syntax To display information about command syntax, enter the command name followed by -?. Entering ROM Monitor Commands ROM monitor commands are case-sensitive. Enter commands exactly as shown. Interrupting ROM Monitor Commands You can end any command by generating a Break (system interrupt) at the console. ROM Monitor Command Syntax Conventions The ROM monitor syntax in this appendix uses the following conventions: •Square brackets [ ] denote an optional element. In the following example, the element abc is not required, but you can specify it if you choose: command [abc] •If a minus option is followed by a colon (for example, [-s:]) you must provide an argument for the option. •A term in italics means that you must fill in the appropriate information. In the following example, you replace the term in italics with the interface type you are using: command interface-type ROM Monitor Command Descriptions Router Management Commands This section lists some useful ROM monitor commands. Refer to the Cisco IOS configuration guides and command references for more information on ROM monitor commands. Boot Commands in the ROM Monitor Functions of Boot Commands The router always boots first from a Cisco IOS image in flash memory, because there is no separate, dedicated boothelper image ([rx]boot). The first image in flash memory functions as the boothelper image, but you can override this by setting the BOOTLDR Monitor environment variable to point to another image. If the ROM monitor does not recognize a device ID specified in the boot command (device does not exist, or command entered incorrectly), the router boots from the first image in flash memory. To boot a router from a Cisco IOS image on a TFTP server (netboot), the installed DRAM must be adequate to hold two uncompressed Cisco IOS images: the image from flash memory and the image downloaded from the TFTP server. If the router is configured to boot from a TFTP server (boot bits in the configuration register are set from 2 to 15), the router first boots from the image in flash memory. It decompresses that image in DRAM, parses the boot system commands, downloads the Cisco IOS image from the TFTP server, and decompresses it in DRAM. After the Cisco IOS image from the TFTP server is in DRAM, the DRAM memory occupied by the boothelper image is released. Note Booting from a TFTP server is useful if the router does not have enough flash memory to hold large images. With a small image in flash memory (just large enough to support the necessary interfaces), the router boots from flash memory, and then the larger image is downloaded from the TFTP server. Entering Boot Commands The boot command syntax is as follows, where: •partition is a partition number in the flash memory. •filename is the Cisco IOS image filename. •tftpserver is the IP address of the TFTP server. •-x directs the router to load the image but not execute the boot process. •-v (verbose) specifies that progress print setting messages and error information be displayed. boot [flash: [partition: [filename]] \| slot0: [partition: [filename]] \| slot1: [partition: [filename]] \| filename tftpserver] [-x] [-v] Some examples of boot commands are as follows: Note In all boot commands, boot can be entered as b. •boot—Boots from the first Cisco IOS image in internal flash memory. •boot flash:—Boots from the first Cisco IOS image in the internal Flash memory. •boot flash: partition:—Boots from the first Cisco IOS image in the specified partition in internal flash memory. •boot flash: filename—Boots from the Cisco specified IOS image in internal flash memory. •boot flash: partition: filename—Boots from the specified Cisco IOS image in the specified partition in internal flash memory. •boot slot0:—(Cisco 2691 only) Boots from the first Cisco IOS image in the first partition in flash memory in slot 0. •boot slot0:2:—(Cisco 2691 only) Boots from the first Cisco IOS image in the second partition in compact flash memory in slot 0. •boot slot0: filename—(Cisco 2691 only) Boots from the specified Cisco IOS image in compact flash memory in slot 0. •boot slot1:3: filename—(Cisco 2691 only) Boots from the specified Cisco IOS image in the third partition in compact flash memory in slot 1. •boot filename tftpserver— Boots from the specified Cisco IOS image on the specified TFTP server (after first booting from flash). For example: boot c2600-i-mz 172.15.19.11 Note Use the CLI commands show version and show hardware to see the source of the currently running Cisco IOS image. Informational Commands in the ROM Monitor dev—(Cisco 2691 only) Lists boot device identifications on the router, for example: rommon 2 > dev Devices in device table: id name flash: internal compact flash slot0: external compact flash eprom: eprom rommon 3 > dir device:[partition:]—Lists the files on the named device. For example: rommon 8> dir flash: File size Checksum File name 2229799 bytes (0x220627) 0x469e C2600-j-m2.113-4T help—Shows a summary of ROM monitor commands (equivalent to ?). meminfo—Displays main memory size, starting address, and available range; size of packet memory; and size of NVRAM. The following example shows the meminfo command: rommon 9> meminfo Main memory size: 32 MB. Available main memory starts at 0xa000e000, size 32704KB IO (packet) memory size: 25 percent of main memory. NVRAM size: 32KB meminfo [-l]—The meminfo command with the -l option shows supported DRAM configurations. The following example shows an example of the meminfo -l command: rommon 10> meminfo -l Supported memory configurations: DIMM 0 DIMM 1 ------------------- 4M 8M-DUAL 16M 32M-DUAL 4M 4M 4M 4M 8M-DUAL 4M 16M 4M 32M-DUAL 8M-DUAL 8M-DUAL 4M 8M-DUAL 8M-DUAL 8M-DUAL 16M 8M-DUAL 32M-DUAL 16M 16M 4M 16M 8M-DUAL 16M 16M 16M 32M-DUAL 32M-DUAL 32M-DUAL 4M 32M-DUAL 8M-DUAL 32M-DUAL 16M 32M-DUAL 32M-DUAL Other Useful ROM Monitor Commands reset or i—Resets and initializes the router, similar to power on. tftpdnld—(Except Cisco 2691) Downloads an image using TFTP from a remote server. See the "Copying an Image from a TFTP Server Using the tftpdnld Command" procedure. Debugging Commands Most debugging commands are functional only when Cisco IOS software has crashed or failed to initialize (boot). Debugging commands should normally be entered only under the direction of a Cisco engineer. If you enter a debugging command and Cisco IOS crash information is not available, the following error message appears: "xxx: kernel context state is invalid, cannot proceed." The following ROM monitor debugging commands provide information about software failures: •stack or k—Produces a stack trace. •context—Views processor context. •frame—Views an individual stack frame. •sysret—Views return information from the last booted system image. This information 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: a SegV exception pc:0x802b1040, error address: 0x802b1040 Stack Trace: FP: 0x80908398, PC: 0x802b102c FP: 0x809083b0, PC: 0x802b0b88 FP: 0x809083d8, PC: 0x8017039c FP: 0x809083e8, PC: 0x8016f764 Configuration Register Commands The configuration register resides in NVRAM. You can view or modify the configuration register from either the ROM monitor or the operating system software. For procedures used to change the configuration register from the operating system, and for information about configuration register settings, see Appendix C, "Configuration Register." To modify the configuration register from the ROM monitor, you can: •Enter the confreg command by itself for menu mode. See the "Modifying the Configuration Register in Menu Mode" section below. •Enter the confreg command plus the new hexidecimal value of the configuration register. See the "Modifying the Configuration Register by Hexidecimal Entry" section. In either case, the new configuration register value is written into NVRAM, but is not effective until you reboot (using the ROM monitor reset command) or power cycle the router. Modifying the Configuration Register in Menu Mode Entering the confreg command without an argument displays the contents of the configuration register, and prompts you to alter the contents by describing the meaning of each bit. The following display shows an example of the confreg command: 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 break/abort has effect 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 Modifying the Configuration Register by Hexidecimal Entry Entering the confreg command plus a hexidecimal value changes the contents of the configuration register. The syntax is confreg [hexnum]; values entered are always interpreted as hexadecimal. The following example changes the value of the configuration register to the factory default: rommon 7> confreg 0x2102 You must reset or power cycle the router for new configuration to take effect. Recovering Cisco IOS Software Images If your Cisco router experiences difficulties and no longer contains a valid Cisco IOS software image in flash memory, you can download a new Cisco IOS image using one of the following ROM monitor commands: •xmodem—(All Cisco 2600 series routers) Use this command to copy a Cisco IOS image from the console, if the computer attached to your console has a terminal emulator with Xmodem capability. See the "Copying an Image from the Console Using the xmodem Command" procedure. Note Downloading a Cisco IOS image from a console is very slow. This procedure should be used only in an emergency and is not recommended for normal Cisco IOS image upgrades. For the fastest possible download from a console, set the console speed to 115200 bps by using the confreg ROM monitor command. See the "Configuration Register Commands" procedure. •tftpdnld—(Except Cisco 2691) Use this command to copy a Cisco IOS image from a TFTP server that is accessible through the FastEthernet 0/0, Ethernet 0/0, or Token Ring 0/0 port. See the "Copying an Image from a TFTP Server Using the tftpdnld Command" procedure. Note The tftpdnld command is not available on the Cisco 2691 router. The recommended method for installing a Cisco IOS image on a Cisco 2691 router is from a CompactFlash memory card loaded in the external CompactFlash memory card slot. See the "Entering Boot Commands" procedure. Copying an Image from the Console Using the xmodem Command Description and Options of the xmodem Command The xmodem command establishes a connection between a console and the router console port for disaster recovery, if both the boot and system images are erased from flash memory. xmodem [filename]—Establishes an Xmodem connection between the console and the router. The optional argument filename specifies the source file containing the Cisco IOS image. Other options include the following: •c—Use cyclic redundancy check (CRC-16). •y—Use Ymodem transfer protocol. •r—Copy the image to dynamic random-access memory (DRAM) for launch. •x—Do not launch image on completion of download. Console Requirements The console computer (PC) must have the following files to use this procedure: •Terminal emulation application program supporting one of the following file transfer protocols: –Xmodem –Xmodem-CRC –Xmodem-1K –Ymodem •Cisco IOS image file Procedure for the xmodem Command To copy a Cisco IOS image from a console to flash memory, perform the following procedure. Note File transfer from a console is slow and will take many minutes. Step 1 Connect a console to the router's console port using the instructions in the "Connecting to a Console Terminal or Modem" section on page 3-20. Step 2 Power up 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 When the source file is found, messages similar to the following appear: Do not start upload program yet... File size Checksum File name 2537948 bytes (0x26b9dc) c2600-i-mz.122-10.bin 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 4 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! The router is now ready to boot from the Cisco IOS image. Enter the reset ROM monitor command to reboot the router. Note If you have set the console speed to 115200, you may want to reset it to the previous speed or to the factory default speed (typically 9600 bps). See the "Configuration Register Commands" procedure. Copying an Image from a TFTP Server Using the tftpdnld Command The tftpdnld command downloads a Cisco IOS software image from a remote server accessible from a FastEthernet, Ethernet, or Token Ring network interface on a Cisco 2600 series router (except Cisco 2691). The tftpdnld command downloads the Cisco IOS software image into flash memory using TFTP. Restrictions on the tftpdnld Command The following software restrictions apply when using the tftpdnld command: •Ethernet and FastEthernet—Accepts and sends only Ethernet V2.0 data packets. •Token Ring—Accepts and sends only Token Ring frames with IEEE802.3 SNAP frames. Does not support any frames with routing information fields (RIFs), limiting all use of the tftpdnld command to a TFTP server on the local ring. If the TFTP server resides off the local ring, you must establish a path to the server through a router or transparent bridge from the local ring. Procedure for the tftpdnld Command Step 1 Specify the required variables, for example: rommon 1> IP_ADDRESS=172.15.19.11 rommon 2> IP_SUBNET_MASK=255.255.255.0 rommon 3> DEFAULT_GATEWAY=172.16.19.1 rommon 4> TFTP_SERVER=172.15.20.10 rommon 5> TFTP_FILE=/tftpboot/c2600-i-mz The syntax for specifying the variables is: VARIABLE_NAME=value The variables that you must specify include the following: •IP_ADDRESS—IP address for the router you are using. •IP_SUBNET_MASK—Subnet mask for the router you are using. •DEFAULT_GATEWAY—Default gateway for the router you are using (not required if the TFTP server is in the same subnet as the router). •TFTP_SERVER—IP address of the server from which you want to download the image file. •TFTP_FILE—Name of the file that you want to download. The following tftpdnld command variables are optional: •TFTP_VERBOSE—Print setting. The default is 1. –0=quiet—After you enter the tftpdnld command, the prompt Do you wish to continue? y/n: is the only information that appears until the command completes successfully or fails. –1=progress—Displays the state of the required tftpdnld command variables. Also displays progress characters to indicate successful and lost packet transmissions. –2=verbose—Displays all progress print setting messages, along with error information. The information provided by this print setting may be useful when debugging interface link and configuration problems that may prevent connecting to the TFTP server. •TFTP_RETRY_COUNT—Number of times from 1 to 65535 that the ROM monitor will retry address resolution protocol (ARP) and acknowledge (ACK). The default is 7 retries. •TFTP_TIMEOUT—Overall timeout of the download operation in seconds. The range is from 1 to 65535 seconds. The default is 7200 seconds. •TFTP_CHECKSUM—Performs a checksum test on the image. 0=checksum off, 1=checksum on. The default is 1. •FE_SPEED_MODE—Sets the Fast Ethernet speed and duplex mode. 0=10 Mbps half-duplex mode, 1=10 Mbps full-duplex mode, 2=100 Mbps half-duplex mode, 3=100 Mbps full-duplex mode, and 4=auto-negotiation. The default is 4. Note Specify the FE_SPEED_MODE variable only for routers with a Fast Ethernet network interface. •TR_SPEED_MODE—Sets the Token Ring speed and duplex mode. 0=4 Mbps half-duplex mode, 1=4 Mbps full-duplex mode, 2=16 Mbps half-duplex mode, and 3=16 Mbps full-duplex mode. The default is 2. Note Specify the TR_SPEED_MODE variable only for routers with a Token Ring network interface; or for routers with both an Ethernet and a Token Ring port, those routers that are set to use the Token Ring port with the tftpdnld command. •TR_1E1R_PORT—Sets the port to be used with the tftpdnld command. 0=Use Ethernet port; 1=Use Token Ring port. The default is 0. Note Specify the TR_1E1R_PORT variable only for those routers with both an Ethernet and a Token Ring port. Step 2 Enter the tftpdnld [-h] [-r] command: Options include the following: •h—Displays the tftpdnld command help screen. •r—Loads the Cisco IOS software image only to DRAM and launches the image without writing the image into flash memory. rommon 6> tftpdnld IP_ADDRESS=172.15.19.11 IP_SUBNET_MASK=255.255.255.0 DEFAULT_GATEWAY=172.16.19.1 TFTP_SERVER=172.15.20.10 TFTP_FILE=/tftpboot/2600-i-mz Invoke this command for disaster recovery only. WARNING: all existing data in all partitions on flash will be lost! Do you wish to continue? y/n: [n]: Step 3 Enter y to download the Cisco IOS software image. When the process is complete, the ROM monitor mode prompt appears on your screen. rommon 7> The router is now ready to boot from the Cisco IOS image. Enter the boot ROM monitor command to reboot the router.
	Terms & Conditions \| Privacy Statement \| Cookie Policy \| Trademarks