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C-3
Cisco Secure Router 520 Series Software Configuration Guide
OL-14210-01
Appendix C ROM Monitor
Command Descriptions
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, see the documentation for that product for information on how to send a Break command.
Command Descriptions
Table C-1 describes the most commonly used ROM monitor commands.
Disaster Recovery with TFTP Download
The standard way to load new software on your router is to use the copy tftp flash privileged EXEC
command from the Cisco
IOS software command-line interface (CLI). However, if the router is unable
to boot 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.
Ta ble C-1 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 [-cyrxu] <destination filename>
-c CRC-16
-y ymodem-batch protocol
-r copy image to dram for launch
-x do not launch on download completion
-u upgrade ROMMON, System will reboot after upgrade
reset or i Resets and initializes the router, similar to a power up.
dir device: Lists the files on the named device; for example, flash memory files:
rommon 4 > dir flash:
Directory of flash:/
2 -rwx 10283208 <date> c870-advsecurityk9-mz
9064448 bytes available (10289152 bytes used)
boot commands
For more information about the ROM monitor boot commands, see the Cisco IOS
Configuration Fundamentals and Network Management Guide.
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 memory.