Cisco 1801, Configuration Manual

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C-3
Cisco 1800 Series Integrated Services Routers (Fixed) Software Configuration Guide
OL-6426-02
Appendix C ROM Monitor
Command Descriptions
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.
TFTP Download Command Variables
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 both required variables and optional variables.
Table 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> c1800-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.