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This appendix describes the Cisco 827 routers ROM monitor (also called the bootstrap program). The ROM monitor firmware runs when the router is powered up or reset and helps to initialize the processor hardware and boot the operating system software. You can perform certain configuration tasks such as recovering a lost password or downloading software over the console port by using ROM monitor. If there is no Cisco IOS software image loaded on the router, the ROM monitor runs the router.
This appendix contains the following sections:
Take these steps to configure the router to boot up in ROM monitor mode the next time it is rebooted:
| Step | Task | Router Prompt | Command | ||
| If there is an enable password configured, enter the enable command and the enable password to enter privileged EXEC mode. | | enable | ||
| Enter global configuration mode. | | configure terminal | ||
| Reset the configuration register. | 820(config)# | config-reg 0x0 | ||
| Exit global configuration mode. | 820(config)# | exit | ||
| Reboot the router with the new configuration register value. The router remains in ROM monitor and does not boot the Cisco IOS software. As long as the configuration value is 0x0, you must manually boot the operating system from the console. Refer to the boot command in the "Command Descriptions" section later in this appendix. | 820 # | reload | ||
| After the router reboots, it is in ROM monitor mode. The number in the prompt increments with each new line. | rommon 1> |
|
 | TimeSaver Break (system interrupt) is always enabled for 60 seconds after the router reboots, regardless of whether it is set to on or off in the configuration register. During this 60-second window, you can break to the ROM monitor prompt by pressing the Break key. |
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 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 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 tftpdnld tftp image download unalias unset an alias unset unset a monitor variable xmodem x/ymodem image download
Commands are case sensitive. You can halt any command by pressing the Break key on a terminal. If you are using a PC, most terminal emulation programs halt a command when you press the Ctrl and the Break keys at the same time. If you are using another type of terminal emulator or terminal emulation software, refer to the documentation for that product for information on how to send a Break command.
This section describes the most commonly used ROM monitor commands:
| Command | Description |
|---|---|
help or ? | Displays a summary of all available ROM monitor commands. |
Displays information about command syntax; for example: rommon 16 > dis -? usage : dis [addr] [length]
The output for this command is slightly different for the xmodem download command: rommon 11 > xmodem -? xmodem: illegal option -- ? usage: xmodem [-cyrx] <destination filename> -c CRC-16 -y ymodem-batch protocol -r copy image to dram for launch -x do not launch on download completion | |
Resets and initializes the router, similar to a power up. | |
Lists boot device identifications on the router; for example: rommon 10> dev Devices in device table: id name flash: flash eprom: eprom | |
Lists the files on the named device; flash, for example: rommon 11> dir flash: File size Checksum File name 2260792 bytes (0x227f38) 0xa326 c827-y6-mz
| |
| Boot Commands | For more information about the ROM monitor boot commands, see the Cisco IOS Configuration Guide and Cisco IOS Command Reference publications. |
b | Boots the first image in Flash memory. |
b flash: [filename] | Attempts to boot the image directly from the first partition of Flash memory. If you do not enter a filename, this command will boot this first image in Flash. |
b flash:2: [filename] | Attempts to boot the image directly from the second partition of Flash memory. If you do not enter a filename, this command will boot this first image in the second partition of Flash memory. |
The standard way to load new software on your router is using the copy tftp flash privileged EXEC command from the Cisco IOS software command-line interface (CLI). However, if the router is unable to boot the Cisco IOS software, you can load new software while in ROM monitor mode.
This section describes how to load a Cisco IOS software image from a remote TFTP server to the router Flash memory. Use the tftpdnld command only for disaster recovery because it erases all existing data in Flash memory before downloading a new software image to the router.
This section describes the system variables that can be set in ROM monitor mode and that are used during the TFTP download process. There are required and optional variables.
These variables must be set with these commands before using the tftpdnld command:
| Variable | Command |
IP address of the router. | IP_ADDRESS= ip_address |
Subnet mask of the router. | IP_SUBNET_MASK= ip_address |
IP address of the default gateway of the router. | DEFAULT_GATEWAY= ip_address |
IP address of the TFTP server from which the software will be downloaded. | TFTP_SERVER= ip_address |
The name of the file that will be downloaded to the router. | TFTP_FILE= filename |
These variables can be set with these commands before using the tftpdnld command:
| Variable | Command |
Configures how the router displays file download progress. 0---No progress is displayed. 1---Exclamation points (!!!) are displayed to indicate file download progress. This is the default setting. 2---Detailed progress is displayed during the file download process; for example: Initializing interface. Interface link state up. ARPing for 1.4.0.1 ARP reply for 1.4.0.1 received. MAC address 00:00:0c:07:ac:01 | TFTP_VERBOSE= setting |
Number of times the router attempts ARP and TFTP download. The default is 7. | TFTP_RETRY_COUNT= retry_times |
Amount of time, in seconds, before the download process times out. The default is 2, 400 seconds (40 minutes). | TFTP_TIMEOUT= time |
Whether or not the router performs a checksum test on the downloaded image: 1---Checksum test is performed. 0---No checksum test is performed. | TFTP_CHECKSUM=setting |
The steps described in this section should be performed while in ROM monitor mode.
Step 1 Use the appropriate commands to enter all the required variables and any optional variables described earlier in this section.
Step 2 Enter the tftpdnld command as follows:
rommon 1 > tftpdnld -r
You will see output similar to the following:
IP_ADDRESS: 1.3.6.7
IP_SUBNET_MASK: 255.255.0.0
DEFAULT_GATEWAY: 1.3.0.1
TFTP_SERVER: 223.255.254.254
TFTP_FILE: c827-bnr2sy-mz.070298
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 If you are sure that you want to continue, enter y in response to the question in the output:
Do you wish to continue? y/n: [n]:y
The router begins to download the new file.
Entering Ctrl-C or Break stops the transfer before the Flash memory is erased.
The virtual configuration register is in nonvolatile RAM (NVRAM) and has the same functionality as other Cisco routers. You can view or modify the virtual configuration register from either the ROM monitor or the operating system software.
To change the virtual configuration register from the ROM monitor, enter confreg or enter the new value of the register in hexadecimal.
The value is always interpreted as hexadecimal. Entering confreg without an argument displays the contents of the virtual configuration register and a prompt to alter the contents by describing the meaning of each bit.
In either case, the new virtual configuration register value is written into NVRAM but does not take effect until you reset or reboot the router.
The following display shows an example of entering the confreg command:
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
You can use console download, a ROM monitor function, to download over the router console port either a software image or a configuration file. After download, the file is either saved to the mini-Flash memory module or to main memory for execution (image files only).
Use console download when you do not have access to a Trivial File Transfer Protocol (TFTP) server.
Following is the syntax and descriptions for the xmodem console download command:
xmodem [-cyrx] destination_file_name
c | (Optional) Performs the download using 16-bit cyclic redundancy check (CRC-16) error checking to validate packets. Default is 8-bit CRC. |
y | (Optional) Sets the router to perform the download using Ymodem protocol. Default is Xmodem protocol. The protocols differ as follows:
|
r | (Optional) Image is loaded into DRAM for execution. Default is to load the image into Flash memory. |
x | (Optional) Image is loaded into DRAM without being executed. |
destination_file_name | The name of the system image file or the system configuration file. In order for the router to recognize it, the name of the configuration file must be router_confg. |
Follow the steps below to run Xmodem:
1. Move the image file to the local drive where the Xmodem will execute.
Because the ROM monitor console download uses the console to perform the data transfer, error messages are only displayed on the console when the data transfer is terminated.
If an error does occur during a data transfer, the transfer is terminated, and an error message is displayed. If you have changed the baud rate from the default rate, the error message is followed by a message telling you to restore the terminal to the baud rate specified in the configuration register.
"xxx: kernel context state is invalid, can not proceed."
The following are ROM monitor debugging commands:
rommon 6> stack Stack trace: PC = 0x801111b0 Frame 00: FP = 0x80005ea8 PC = 0x801111b0 Frame 01: FP = 0x80005eb4 PC = 0x80113694 Frame 02: FP = 0x80005f74 PC = 0x8010eb44 Frame 03: FP = 0x80005f9c PC = 0x80008118 Frame 04: FP = 0x80005fac PC = 0x80008064 Frame 05: FP = 0x80005fc4 PC = 0xfff03d70
rommon 7> context CPU context of the most recent exception: PC = 0x801111b0 MSR = 0x00009032 CR = 0x53000035 LR = 0x80113694 CTR = 0x801065e4 XER = 0xa0006d36 DAR = 0xffffffff DSISR = 0xffffffff DEC = 0xffffffff TBU = 0xffffffff TBL = 0xffffffff IMMR = 0xffffffff R0 = 0x00000000 R1 = 0x80005ea8 R2 = 0xffffffff R3 = 0x00000000 R4 = 0x8fab0d76 R5 = 0x80657d00 R6 = 0x80570000 R7 = 0x80570000 R8 = 0x00000000 R9 = 0x80570000 R10 = 0x0000954c R11 = 0x00000000 R12 = 0x00000080 R13 = 0xffffffff R14 = 0xffffffff R15 = 0xffffffff R16 = 0xffffffff R17 = 0xffffffff R18 = 0xffffffff R19 = 0xffffffff R20 = 0xffffffff R21 = 0xffffffff R22 = 0xffffffff R23 = 0xffffffff R24 = 0xffffffff R25 = 0xffffffff R26 = 0xffffffff R27 = 0xffffffff R28 = 0xffffffff R29 = 0xffffffff R30 = 0xffffffff R31 = 0xffffffff
rommon 8> sysret System Return Info: count: 19, reason: user break pc:0x801111b0, error address: 0x801111b0 Stack Trace: FP: 0x80005ea8, PC: 0x801111b0 FP: 0x80005eb4, PC: 0x80113694 FP: 0x80005f74, PC: 0x8010eb44 FP: 0x80005f9c, PC: 0x80008118 FP: 0x80005fac, PC: 0x80008064 FP: 0x80005fc4, PC: 0xfff03d70 FP: 0x80005ffc, PC: 0x00000000 FP: 0x00000000, PC: 0x00000000
rommon 9> meminfo Main memory size: 40 MB. Available main memory starts at 0x10000, size 40896KB IO (packet) memory size: 5 percent of main memory. NVRAM size: 32KB
Posted: Fri Apr 7 14:57:55 PDT 2000
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