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APPENDIXC
ROM Monitor
The ROM monitor firmware runs when the router is powered up or reset. The firmware helps to initialize 
the processor hardware and boot the operating system software. You can use the ROM monitor to 
perform certain configuration tasks, such as recovering a lost password or downloading software over 
the console port. If there is no Cisco
 IOS software image loaded on the router, the...

 
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Appendix C      ROM Monitor
  ROM Monitor Commands
TimesaverBreak (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. 
ROM Monitor Commands
Enter ? or help at the ROM monitor prompt to display a list of...

 
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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...

 
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Appendix C      ROM Monitor
  Disaster Recovery with TFTP Download
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. 
NoteThe commands described in this section are case  sensitive and must be entered exactly as shown.
Required...

 
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Appendix C      ROM Monitor   Disaster Recovery with TFTP Download
Optional Variables
These variables can be set with these commands before using the tftpdnld command:
VariableCommand
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...

 
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Appendix C      ROM Monitor
  Configuration Register
You will see output similar to the following:
IP_ADDRESS: 10.3.6.7
IP_SUBNET_MASK: 255.255.0.0DEFAULT_GATEWAY: 10.3.0.1
TFTP_SERVER: 192.168.254.254
TFTP_FILE: c870-advsecurityk9-mzDo you wish to continue? y/n:  [n]:
Step 3If 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...

 
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Appendix C      ROM Monitor
  Console Download
The following display shows an example of entering the confreg command:
rommon 7> confreg
      Configuration Summary
enabled are:
console baud: 9600boot: the ROM Monitor
 
do you wish to change the configuration? y/n  [n]:  yenable  “diagnostic mode”? y/n  [n]:  y
enable  “use net in IP bcast address”? y/n  [n]:  
enable  “load rom after netboot fails”? y/n...

 
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Appendix C      ROM Monitor
  Debug Commands
Command Description
The following are the syntax and descriptions for the  xmodem console download command:
xmodem [-cyrx]  destination_file_name
cOptional. Performs the download using 16-bit cyclic redundancy check (CRC-16) error 
checking to validate packets. Default is 8-bit CRC.
yOptional. Sets the router to perform the do wnload using Ymodem protocol. The...

 
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Appendix C      ROM Monitor
  Debug Commands
The following are ROM monitor debugging commands:
 stack or k—Produces a stack trace; for example:
rommon 6> stack
Stack trace:
PC = 0x801111b0Frame 00: FP = 0x80005ea8    PC = 0x801111b0
Frame 01: FP = 0x80005eb4    PC = 0x80113694
Frame 02: FP = 0x80005f74    PC = 0x8010eb44Frame 03: FP = 0x80005f9c    PC = 0x80008118
Frame 04: FP = 0x80005fac    PC =...

 
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Appendix C      ROM Monitor
  Exiting the ROM Monitor
Exiting the ROM Monitor
You must set the configuration register to a value from 0x2 to 0xF for the router to boot a Cisco IOS 
image from flash memory upon startup or reloading. 
The following example shows how to reset the configuration register and cause the router to boot a 
Cisco
 IOS image stored in flash memory:
rommon 1 > confreg 0x2101
You must...