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Table Of Contents
Platforms Supported by This Document
Prerequisites for Using the ROM Monitor
Information About the ROM Monitor
ROM Monitor Mode Command Prompt
Why Is My Router in ROM Monitor Mode?
When Would I Use the ROM Monitor?
Tips for Using ROM Monitor Commands
How to Use the ROM Monitor—Typical Tasks
Using the Break Key Sequence to Interrupt the System Reload and Enter ROM Monitor Mode
Setting the Configuration Register to Boot to ROM Monitor Mode
Displaying Commands and Command Syntax in ROM Monitor Mode (?, help, -?)
Displaying Files in a File System (dir)
Downloading Files over the Router Console Port (xmodem)
Modifying the Configuration Register (confreg)
Obtaining Information on USB Flash Devices
Modifying the I/O Memory (iomemset)
Recovering the System Image (tftpdnld)
Troubleshooting Crashes and Hangs (stack, context, frame, sysret, meminfo)
ROM Monitor Console Communication Failure
Using the ROM Monitor
Many users do not use the ROM monitor at all, unless during power up or reload, the router does not find a valid system image, the last digit of the boot field in the configuration register is 0, or you enter the Break key sequence during the first 60 seconds after reloading the router.
This document describes how to use the ROM monitor to manually load a system image, upgrade the system image when there are no TFTP servers or network connections, or for disaster recovery.
Contents
•
Platforms Supported by This Document
•
Prerequisites for Using the ROM Monitor
•
Information About the ROM Monitor
•
How to Use the ROM Monitor—Typical Tasks
Platforms Supported by This Document
This document describes use of the ROM monitor with the following platforms:
•
Cisco 1841 series routers
•
Cisco 2800 series routers
•
Cisco 3800 series routers
Prerequisites for Using the ROM Monitor
Connect a terminal or PC to the router console port. For help, see the quick start guide or the hardware installation guide for your router.
Information About the ROM Monitor
Before using the ROM monitor, you should understand the following concepts:
•
ROM Monitor Mode Command Prompt
•
Why Is My Router in ROM Monitor Mode?
•
When Would I Use the ROM Monitor?
•
Tips for Using ROM Monitor Commands
ROM Monitor Mode Command Prompt
The ROM monitor uses the rommon x > command prompt. The x variable begins at 1 and increments each time you press Return or Enter in ROM monitor mode.
Why Is My Router in ROM Monitor Mode?
Your router boots to ROM monitor mode when one of the following occurs:
•
During power up or reload, the router does not find a valid system image.
•
The last digit of the boot field in the configuration register is 0 (for example, 0x100 or 0x0).
•
You enter the Break key sequence during the first 60 seconds after reloading the router.
To exit ROM monitor mode, see the "Exiting ROM Monitor Mode" section.
When Would I Use the ROM Monitor?
Many users do not use the ROM monitor at all, except in the following uncommon situations:
•
Manually loading a system image—You can load a system image without configuring the router to attempt to load that image in future system reloads or power-cycles. This can be useful for testing a new system image or for troubleshooting. See the "Loading a System Image (boot)" section.
•
Upgrading the system image when there are no TFTP servers or network connections, and a direct PC connection to the router console is the only viable option—See information about upgrading the system image in configuration documentation for your router.
•
During troubleshooting if the router crashes and hangs—See the "Troubleshooting Crashes and Hangs (stack, context, frame, sysret, meminfo)" section.
•
Disaster recovery—Use one of the following methods for recovering the system image or configuration file:
–
Console download (xmodem)—Use this method if the computer that is attached to your console has a terminal emulator that supports the Xmodem Protocol. See the "Downloading Files over the Router Console Port (xmodem)" section.
For more information about using the Xmodem protocol, see the Xmodem Console Download Procedure Using ROMmon at the following URL:
http://www.cisco.com/warp/public/130/xmodem_generic.html
–
TFTP download (tftpdnld)—Use this method if you can connect a TFTP server directly to the fixed LAN port on your router. See the "Recovering the System Image (tftpdnld)" section.
Note
Recovering the system image is different from upgrading the system image. You need to recover the system image if it becomes corrupt or if it is deleted because of a disaster that affects the memory device severely enough to require deleting all data on the memory device in order to load a system image.
Tips for Using ROM Monitor Commands
•
ROM monitor commands are case sensitive.
•
You can halt any ROM monitor command by entering the Break key sequence (Ctrl-Break) on the PC or terminal. The Break key sequence varies, depending on the software on your PC or terminal. If Ctrl-Break does not work, see the Standard Break Key Sequence Combinations During Password Recovery tech note.
•
To find out which commands are available on your router and to display command syntax options, see the "Displaying Commands and Command Syntax in ROM Monitor Mode (?, help, -?)" section.
Accessibility
This product can be configured using the Cisco command-line interface (CLI). The CLI conforms to accessibility code 508 because it is text based and because it relies on a keyboard for navigation. All functions of the router can be configured and monitored through the CLI.
For a complete list of guidelines and Cisco products adherence to accessibility, see Cisco Accessibility Products at the following URL:
http://www.cisco.com/web/about/responsibility/accessibility/products
How to Use the ROM Monitor—Typical Tasks
This section provides the following procedures:
•
Displaying Commands and Command Syntax in ROM Monitor Mode (?, help, -?)
•
Displaying Files in a File System (dir)
•
Loading a System Image (boot)
•
Downloading Files over the Router Console Port (xmodem)
•
Modifying the Configuration Register (confreg)
•
Obtaining Information on USB Flash Devices
•
Modifying the I/O Memory (iomemset)
•
Recovering the System Image (tftpdnld)
•
Troubleshooting Crashes and Hangs (stack, context, frame, sysret, meminfo)
Note
This section does not describe how to perform all possible ROM monitor tasks. Use the command help to perform any tasks that are not described in this document. See the "Displaying Commands and Command Syntax in ROM Monitor Mode (?, help, -?)" section.
Entering ROM Monitor Mode
This section provides two ways to enter ROM monitor mode:
•
Using the Break Key Sequence to Interrupt the System Reload and Enter ROM Monitor Mode
•
Setting the Configuration Register to Boot to ROM Monitor Mode
Prerequisites
Connect a terminal or PC to the router console port. For help, see the quick start guide that shipped with your router or see the hardware installation guide for your router.
Using the Break Key Sequence to Interrupt the System Reload and Enter ROM Monitor Mode
This section describes how to enter ROM monitor mode by reloading the router and entering the Break key sequence.
SUMMARY STEPS
1.
enable
2.
reload
3.
Press Ctrl-Break.
DETAILED STEPS
Command or Action PurposeStep 1
enable
Example:Router> enable
Enables privileged EXEC mode.
•
Enter your password if prompted.
Step 2
reload
Example:Router# reload
Reloads the operating system.
Step 3
Press Ctrl-Break.
Example:Router# send break
Interrupts the router reload and enters ROM monitor mode.
•
You must perform this step within 60 seconds after you enter the reload command.
•
The Break key sequence varies, depending on the software on your PC or terminal. If Ctrl-Break does not work, see the Standard Break Key Sequence Combinations During Password Recovery tech note.
Examples
This section provides the following example:
Sample Output for the reload Command
Use break key sequence to enter rom monitorRouter# reload
Proceed with reload? [confirm]*Sep 23 15:54:25.871: %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload command.telnet> send break
*** System received an abort due to Break Key ***signal= 0x3, code= 0x0, context= 0x431aaf40PC = 0x4008b5dc, Cause = 0x20, Status Reg = 0x3400c102rommon 1 >Troubleshooting Tips
The Break key sequence varies, depending on the software on your PC or terminal. See the Standard Break Key Sequence Combinations During Password Recovery tech note.
What to Do Next
•
Proceed to the "Displaying Commands and Command Syntax in ROM Monitor Mode (?, help, -?)" section.
•
If you use the Break key sequence to enter ROM monitor mode when the router would otherwise have booted the system image, you can exit ROM monitor mode by doing one of the following:
–
Enter the i or reset command, which restarts the booting process and loads the system image.
–
Enter the cont command, which continues the booting process and loads the system image.
Setting the Configuration Register to Boot to ROM Monitor Mode
This section describes how to enter ROM monitor mode by setting the configuration register to boot to ROM monitor mode at the next system reload or power-cycle.
CautionDo not set the configuration register by using the config-register 0x0 command after you have set the baud rate. To set the configuration register without affecting the baud rate, use the the current configuration register setting by entering the show ver | inc configuration command, and then replacing the last (rightmost) number with a 0 in the configuration register command.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
config-register 0x0
4.
exit
5.
write memory
6.
reload
DETAILED STEPS
Examples
The following example shows how to set the configuration register to boot to ROM monitor mode:
Router>Router> enable
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.Router(config)# config-register 0x0
Router(config)# exit
Router#*Sep 23 16:01:24.351: %SYS-5-CONFIG_I: Configured from console by consoleRouter# write memory
Building configuration...[OK]Router# reload
Proceed with reload? [confirm]*Sep 23 16:01:41.571: %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload command.System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)Technical Support: http://www.cisco.com/techsupportCopyright (c) 2006 by cisco Systems, Inc.Initializing memory for ECC.Router platform with 262144 Kbytes of main memoryMain memory is configured to 64 bit mode with ECC enabledReadonly ROMMON initializedrommon 1 >What to Do Next
Proceed to the "Displaying Commands and Command Syntax in ROM Monitor Mode (?, help, -?)" section.
Displaying Commands and Command Syntax in ROM Monitor Mode (?, help, -?)
This section describes how to display ROM monitor commands and command syntax options.
SUMMARY STEPS
1.
?
or
help2.
command -?
DETAILED STEPS
Examples
This section provides the following examples:
•
Sample Output for the ? or help ROM Monitor Command
•
Sample Output for the xmodem -? ROM Monitor Command
Sample Output for the ? or help ROM Monitor Command
rommon 1 > ?
alias set and display aliases commandboot boot up an external processbreak set/show/clear the breakpointconfreg configuration register utilitycont continue executing a downloaded imagecontext display the context of a loaded imagecookie display contents of cookie PROM in hexdev list the device tabledir list files in file systemdis display instruction streamdnld serial download a program moduleframe print out a selected stack framehelp monitor builtin command helphistory monitor command historyiomemset set IO memory percentmeminfo main memory informationrepeat repeat a monitor commandreset system resetrommon-pref select ROMMONset display the monitor variablesshowmon display currently selected ROM monitorstack produce a stack tracesync write monitor environment to NVRAMsysret print out info from last system returntftpdnld tftp image downloadunalias unset an aliasunset unset a monitor variablexmodem x/ymodem image downloadSample Output for the xmodem -? ROM Monitor 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 completionFor more information about using Xmodem, see the Xmodem Console Download Procedure Using ROMmon at the following URL:
http://www.cisco.com/warp/public/130/xmodem_generic.html
Displaying Files in a File System (dir)
To display a list of the files and directories in the file system, use the dir command, as shown in the following example:
rommon 4 > dir flash:
program load complete, entry point: 0x8000f000, size: 0xcb80Directory of flash:3934 14871760 -rw- c2800nm-ipbase-mz.124-37211 1447053 -rw- C2800NM_RM2.srecrommon 5 > dir usbflash1:
program load complete, entry point: 0x8000f000, size: 0x3d240Directory of usbflash1:2 14871760 -rw- c2800nm-ipbase-mz.124-3Loading a System Image (boot)
This section describes how to load a system image by using the boot ROM monitor command.
Prerequisites
Determine the filename and location of the system image that you want to load.
SUMMARY STEPS
1.
boot
or
boot flash:[filename]
or
boot filename tftpserver
or
boot [filename]or
boot usbflash<x>:[filename]
DETAILED STEPS
Examples
The following example shows how to load boot flash memory and USB boot flash memory:
rommon 7 > boot flash:[filename]
program load complete, entry point: 0x8000f000, size: 0xcb80program load complete, entry point: 0x8000f000, size: 0xe2eb30Self decompressing the image : ########################################################################################## ############################################################### [OK]Smart Init is enabledSmart init is sizing iomemID MEMORY_REQ TYPE0003E9 0X003DA000 Router Mainboard0X0014B430 DSP SIMM0X000021B8 Onboard USB0X002C29F0 public buffer pools0X00211000 public particle poolsTOTAL: 0X009FAFD8If any of the above Memory Requirements are"UNKNOWN", you may be using an unsupportedconfiguration or there is a software problem andsystem operation may be compromised.Rounded IOMEM up to: 10Mb.Using 3 percent iomem. [10Mb/256Mb]Restricted Rights LegendUse, duplication, or disclosure by the Government issubject to restrictions as set forth in subparagraph(c) of the Commercial Computer Software - RestrictedRights clause at FAR sec. 52.227-19 and subparagraph(c) (1) (ii) of the Rights in Technical Data and ComputerSoftware clause at DFARS sec. 252.227-7013.cisco Systems, Inc.170 West Tasman DriveSan Jose, California 95134-1706Cisco IOS Software, 2800 Software (C2800NM-IPBASE-M), Version 12.4(3), RELEASE SOFTWARE (fc2)Technical Support: http://www.cisco.com/techsupportCopyright (c) 1986-2005 by Cisco Systems, Inc.Compiled Fri 22-Jul-05 11:37 by hqluongImage text-base: 0x40098478, data-base: 0x41520000Port Statistics for unclassified packets is not turned on.Cisco Router (revision 48.46) with 251904K/10240K bytes of memory.Processor board ID2 Gigabit Ethernet interfaces2 Serial(sync/async) interfaces2 Channelized T1/PRI portsDRAM configuration is 64 bits wide with parity enabled.239K bytes of non-volatile configuration memory.253160K bytes of USB Flash usbflash1 (Read/Write)127104K bytes of ATA CompactFlash (Read/Write)Press RETURN to get started!*Sep 23 16:11:42.603: %USB_HOST_STACK-6-USB_DEVICE_CONNECTED: A Full speed USB device has been inserted in port 1.*Sep 23 16:11:43.011: %LINK-3-UPDOWN: Interface GigabitEthernet0/0, changed state to up*Sep 23 16:11:43.383: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up*Sep 23 16:11:43.943: %LINK-3-UPDOWN: Interface Serial0/3/0, changed state to down*Sep 23 16:11:43.947: %LINK-3-UPDOWN: Interface Serial0/3/1, changed state to down*Sep 23 16:11:43.955: %USBFLASH-5-CHANGE: usbflash1 has been inserted!*Sep 23 16:11:44.011: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up*Sep 23 16:11:44.383: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down*Sep 23 16:11:44.943: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3/0, changed state to down*Sep 23 16:11:44.947: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3/1, changed state to down*Sep 23 16:11:46.115: %SYS-5-CONFIG_I: Configured from memory by console*Sep 23 16:11:46.327: %SYS-5-RESTART: System restarted --Cisco IOS Software, 2800 Software (C2800NM-IPBASE-M), Version 12.4(3), RELEASE SOFTWARE (fc2)Technical Support: http://www.cisco.com/techsupportCopyright (c) 1986-2005 by Cisco Systems, Inc.Compiled Fri 22-Jul-05 11:37 by hqluong*Sep 23 16:11:46.331: %SNMP-5-COLDSTART: SNMP agent on host Router is undergoing a cold start*Sep 23 16:11:46.539: %SYS-6-BOOTTIME: Time taken to reboot after reload = 605 seconds*Sep 23 16:11:46.735: %CONTROLLER-5-UPDOWN: Controller T1 0/2/0, changed state to down (LOS detected)*Sep 23 16:11:46.735: %CONTROLLER-5-UPDOWN: Controller T1 0/2/1, changed state to down (LOS detected)*Sep 23 16:11:48.055: %LINK-5-CHANGED: Interface GigabitEthernet0/1, changed state to administratively down*Sep 23 16:11:48.067: %LINK-5-CHANGED: Interface Serial0/3/0, changed state to administratively down*Sep 23 16:11:48.079: %LINK-5-CHANGED: Interface Serial0/3/1, changed state to administratively downRouter>rommon 1 > boot usbflash1:imageprogram load complete, entry point: 0x8000f000, size: 0x3d240program load complete, entry point: 0x8000f000, size: 0xe2eb30Self decompressing the image : ########################################################################################## ############################################################### [OK]Smart Init is enabledSmart init is sizing iomemID MEMORY_REQ TYPE0003E9 0X003DA000 Router Mainboard0X0014B430 DSP SIMM0X000021B8 Onboard USB0X002C29F0 public buffer pools0X00211000 public particle poolsTOTAL: 0X009FAFD8If any of the above Memory Requirements are"UNKNOWN", you may be using an unsupportedconfiguration or there is a software problem andsystem operation may be compromised.Rounded IOMEM up to: 10Mb.Using 3 percent iomem. [10Mb/256Mb]Restricted Rights LegendUse, duplication, or disclosure by the Government issubject to restrictions as set forth in subparagraph(c) of the Commercial Computer Software - RestrictedRights clause at FAR sec. 52.227-19 and subparagraph(c) (1) (ii) of the Rights in Technical Data and ComputerSoftware clause at DFARS sec. 252.227-7013.cisco Systems, Inc.170 West Tasman DriveSan Jose, California 95134-1706Cisco IOS Software, 2800 Software (C2800NM-IPBASE-M), Version 12.4(3), RELEASE SOFTWARE (fc2)Technical Support: http://www.cisco.com/techsupportCopyright (c) 1986-2005 by Cisco Systems, Inc.Compiled Fri 22-Jul-05 11:37 by hqluongImage text-base: 0x40098478, data-base: 0x41520000Port Statistics for unclassified packets is not turned on.Cisco Router (revision 48.46) with 251904K/10240K bytes of memory.Processor board ID2 Gigabit Ethernet interfaces2 Serial(sync/async) interfaces2 Channelized T1/PRI portsDRAM configuration is 64 bits wide with parity enabled.239K bytes of non-volatile configuration memory.253160K bytes of USB Flash usbflash1 (Read/Write)127104K bytes of ATA CompactFlash (Read/Write)Press RETURN to get started!*Sep 23 16:19:56.611: %USB_HOST_STACK-6-USB_DEVICE_CONNECTED: A Full speed USB device has been inserted in port 1.*Sep 23 16:19:57.015: %LINK-3-UPDOWN: Interface GigabitEthernet0/0, changed state to up*Sep 23 16:19:57.391: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up*Sep 23 16:19:57.951: %LINK-3-UPDOWN: Interface Serial0/3/0, changed state to down*Sep 23 16:19:57.955: %LINK-3-UPDOWN: Interface Serial0/3/1, changed state to down*Sep 23 16:19:57.963: %USBFLASH-5-CHANGE: usbflash1 has been inserted!*Sep 23 16:19:58.015: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up*Sep 23 16:19:58.391: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down*Sep 23 16:19:58.951: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3/0, changed state to down*Sep 23 16:19:58.955: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3/1, changed state to down*Sep 23 16:20:00.139: %SYS-5-CONFIG_I: Configured from memory by console*Sep 23 16:20:00.351: %SYS-5-RESTART: System restarted --Cisco IOS Software, 2800 Software (C2800NM-IPBASE-M), Version 12.4(3), RELEASE SOFTWARE (fc2)Technical Support: http://www.cisco.com/techsupportCopyright (c) 1986-2005 by Cisco Systems, Inc.Compiled Fri 22-Jul-05 11:37 by hqluong*Sep 23 16:20:00.355: %SNMP-5-COLDSTART: SNMP agent on host Router is undergoing a cold start*Sep 23 16:20:00.567: %SYS-6-BOOTTIME: Time taken to reboot after reload = 87 seconds*Sep 23 16:20:00.763: %CONTROLLER-5-UPDOWN: Controller T1 0/2/0, changed state to down (LOS detected)*Sep 23 16:20:00.763: %CONTROLLER-5-UPDOWN: Controller T1 0/2/1, changed state to down (LOS detected)*Sep 23 16:20:02.083: %LINK-5-CHANGED: Interface GigabitEthernet0/1, changed state to administratively down*Sep 23 16:20:02.091: %LINK-5-CHANGED: Interface Serial0/3/0, changed state to administratively down*Sep 23 16:20:02.103: %LINK-5-CHANGED: Interface Serial0/3/1, changed state to administratively downRouter>What to Do Next
If you want to configure the router to load a specified image at the next system reload or power-cycle, see the following documents:
•
"Booting Commands" chapter of the Cisco IOS Configuration Fundamentals Command Reference
•
Cisco IOS Configuration Fundamentals and Network Management Configuration Guide
Downloading Files over the Router Console Port (xmodem)
This section describes how to download a file over the router console port by using the Xmodem Protocol. Use the console download function when you do not have access to a TFTP server but need to download a system image or configuration file to the router. This procedure can also be used when there are no TFTP servers or network connections, and a direct PC connection to the router console is the only viable option.
For more information about using Xmodem, see the Xmodem Console Download Procedure Using ROMmon at the following URL:
http://www.cisco.com/warp/public/130/xmodem_generic.html
Prerequisites
•
Download the file to your PC. Go to the Software Center at the following URL:
http://www.cisco.com/public/sw-center/index.shtml.•
Connect your PC to the router console port and launch a terminal emulator program. To see examples for how to perform this task for similar routers, see the Xmodem Console Download Procedure Using ROMmon tech note.
Restrictions
•
If you use a PC to download a file over the router console port at 115,200 bps, make sure that the PC serial port uses a 16550 universal asynchronous receiver/transmitter (UART).
•
If the PC serial port does not use a 16550 UART, we recommend using a speed equal to or lower than 38,400 bps for downloading a file over the console port.
•
Transfer using the xmodem command works only on the console port.
•
You can only download files to the router. You cannot use the xmodem command to retrieve files from the router.
•
Because the ROM monitor console download uses the console to perform the data transfer, error messages are displayed on the console only after the data transfer is terminated. If an error occurs during console download, the download is terminated, and an error message is displayed. If you changed the baud rate from the default rate, the error message is followed by a message that tells you to restore the terminal to the baud rate that is specified in the configuration register.
SUMMARY STEPS
1.
xmodem [-[c][y][r][x]] destination-file-name
DETAILED STEPS
Step 1
xmodem [-[c][y][r][x]] destination-file-name
Use this command to download a file over the console port using the ROM monitor. For example:
rommon > xmodem -c c2801-is-mz.122-10a.binSee Table 1 for xmodem command syntax descriptions.
What to Do Next
If you want to configure the router to load a specified image at the next system reload or power-cycle, see the following documents:
•
"Booting Commands" chapter of the Cisco IOS Configuration Fundamentals Command Reference
•
Cisco IOS Configuration Fundamentals and Network Management Configuration Guide
Modifying the Configuration Register (confreg)
This section describes how to modify the configuration register by using the confreg ROM monitor command. You can also modify the configuration register setting from the Cisco IOS command-line interface (CLI) by using the config-register command in global configuration mode. For more information on the config-register command in global configuration mode and on using the confreg command in ROM monitor mode, see the Cisco IOS Configuration Fundamentals Command Reference.
CautionDo not set the configuration register by using the config-register 0x0 command after setting the baud rate. To set the configuration register without affecting the baud rate, use the the current configuration register setting by entering the show ver | inc configuration command and then replacing the last (rightmost) number with a 0 in the configuration register command.
Prerequisites
To learn about the configuration register and the function of each of the 16 bits, see the Changing the Configuration Register Settings document.
Restrictions
The modified configuration register value is automatically written into NVRAM, but the new value does not take effect until you reset or power-cycle the router.
SUMMARY STEPS
1.
confreg [value]
DETAILED STEPS
Examples
In the following example, the configuration register is set to boot the system image from flash memory:
rommon 3 > confreg 0x2102In the following example, no value is entered; therefore, the system prompts for each bit in the register:
rommon 7 > confregConfiguration Summaryenabled are:console baud: 9600boot: the ROM Monitordo you wish to change the configuration? y/n [n]: yenable "diagnostic mode"? y/n [n]: yenable "use net in IP bcast address"? y/n [n]: yenable "load rom after netboot fails"? y/n [n]: yenable "use all zero broadcast"? y/n [n]: yenable "break/abort has effect"? y/n [n]: yenable "ignore system config info"? y/n [n]: ychange console baud rate? y/n [n]: yenter rate: 0 = 9600, 1 = 4800, 2 = 1200, 3 = 2400 [0]: 0change the boot characteristics? y/n [n]: yenter to boot:0 = ROM Monitor1 = the boot helper image2-15 = boot system[0]: 0Configuration Summaryenabled are:diagnostic modeconsole baud: 9600boot: the ROM Monitorrommon 8>Obtaining Information on USB Flash Devices
This section describes how to obtain information on USB devices that are installed in the router. For instructions on booting from a USB flash device, see the "Loading a System Image (boot)" section.
SUMMARY STEPS
1.
dir usbflash [x]:
2.
dev
DETAILED STEPS
Examples
Sample Output for the dir usbFlash Command
rommon > dir usbflash0:
Directory of usbflash0:
2 18978364 -rw- c3845-entbasek9-mz.124-0.5
Sample Output for the dev ROM Monitor Commandrommon 2 > dev
Devices in device table:
id name
flash: compact flash
bootflash: boot flash
usbflash0: usbflash0
usbflash1: usbflash1
eprom: eprom
Modifying the I/O Memory (iomemset)
This section describes how to modify the I/O memory by using the memory-size iomemset command.
Note
Use the iomemset command only if it is needed for temporarily setting the I/O memory from ROM monitor mode. Using this command improperly can adversely affect the functioning of the router.
The Cisco IOS software can override the I/O memory percentage if the memory-size iomem command is set in the NVRAM configuration. If the Cisco IOS command is present in the NVRAM configuration, the I/O memory percentage set in the ROM monitor with the iomemset command is used only the first time the router is booted up. Subsequent reloads use the I/O memory percentage set by using the memory-size iomem command that is saved in the NVRAM configuration.
If you need to set the router I/O memory permanently by using a manual method, use the memory-size iomem Cisco IOS command. If you set the I/O memory from the Cisco IOS software, you must restart the router for I/O memory to be set properly.
SUMMARY STEPS
1.
iomemset i/o-memory percentage
DETAILED STEPS
Command or Action PurposeStep 1
iomemset i/o-memory percentage
Example:rommon> iomemset 15
•
Reallocates the percentage of DRAM used for I/O memory and processor memory.
Examples
In the following example, the percentage of DRAM used for I/O memory is set to 15:
rommon 2 > iomemset usage: iomemset [smartinit | 5 | 10 | 15 | 20 | 25 | 30 | 40 | 50 ] rommon 3 > rommon 3 > iomemset 15 Invoking this command will change the io memory percent *****WARNING:IOS may not keep this value***** Do you wish to continue? y/n: [n]: yrommon 4 > meminfo -------------------------------------------------
Current Memory configuration is:Onboard SDRAM: Size = 128 MB : Start Addr = 0x10000000-----Bank 0 128 MB-----Bank 1 0 MBDimm 0: Size = 256 MB : Start Addr = 0x00000000-----Bank 0 128 MB-----Bank 1 128 MB-------------------------------------------------Main memory size: 384 MB in 64 bit mode.Available main memory starts at 0xa0015000, size 393132KBIO (packet) memory size: 10 percent of main memory.NVRAM size: 191KBRecovering the System Image (tftpdnld)
This section describes how to download a Cisco IOS software image from a remote TFTP server to the router flash memory by using the tftpdnld command in ROM monitor mode.
CautionUse the tftpdnld command only for disaster recovery because it can erase all existing data in flash memory before it downloads a new software image to the router.
Before you can enter the tftpdnld command, you must set the ROM monitor environment variables.
Prerequisites
Connect the TFTP server to a fixed network port on your router.
Restrictions
•
LAN ports on network modules or interface cards are not active in ROM monitor mode. Therefore, only a fixed port on your router can be used for TFTP download. This can be a fixed Ethernet port on the router, that is either of the two Gigabit Ethernet ports on Cisco routers with those ports.
•
You can only download files to the router. You cannot use the tftpdnld command to retrieve files from the router.
SUMMARY STEPS
1.
IP_ADDRESS=ip_address
2.
IP_SUBNET_MASK=ip_address
3.
DEFAULT_GATEWAY=ip_address
4.
TFTP_SERVER=ip_address
5.
TFTP_FILE=[directory-path/]filename
6.
FE_PORT=[0 | 1]
7.
FE_SPEED_MODE=[0 | 1 | 2 | 3 | 4 | 5]
8.
GE_PORT=[0 | 1]
9.
GE_SPEED_MODE=[0 | 1 | 2 | 3 | 4 | 5]
10.
MEDIA_TYPE=[0 | 1]
11.
TFTP_CHECKSUM=[0 | 1]
12.
TFTP_DESTINATION=[flash: | usbflash0: | usbflash1:]
13.
TFTP_MACADDR=MAC_address
14.
TFTP_RETRY_COUNT=retry_times
15.
TFTP_TIMEOUT=time
16.
TFTP_VERBOSE=setting
17.
set
18.
tftpdnld [-hr]
19.
y
DETAILED STEPS
Examples
Sample Output for Recovering the System Image (tftpdnld)
rommon 16 > IP_ADDRESS=171.68.171.0rommon 17 > IP_SUBNET_MASK=255.255.254.0rommon 18 > DEFAULT_GATEWAY=171.68.170.3rommon 19 > TFTP_SERVER=171.69.1.129rommon 20 > TFTP_FILE=c2801-is-mz.113-2.0.3.Qrommon 21 > tftpdnldIP_ADDRESS: 171.68.171.0IP_SUBNET_MASK: 255.255.254.0DEFAULT_GATEWAY: 171.68.170.3TFTP_SERVER: 171.69.1.129TFTP_FILE: c2801-is-mz.113-2.0.3.QInvoke 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]: yReceiving c2801-is-mz.113-2.0.3.Q from 171.69.1.129 !!!!!.!!!!!!!!!!!!!!!!!!!.!!File reception completed.Copying file c2801-is-mz.113-2.0.3.Q to flash.Erasing flash at 0x607c0000program flash location 0x60440000rommon 22 >Sample Output for the set ROM Monitor Command
rommon 3 > setPS1=rommon ! >IP_ADDRESS=172.18.16.76IP_SUBNET_MASK=255.255.255.192DEFAULT_GATEWAY=172.18.16.65TFTP_SERVER=172.18.16.2TFTP_FILE=anyname/rel22_Jan_16/c2801-i-mzWhat to Do Next
If you want to configure the router to load a specified image at the next system reload or power-cycle, see the following documents:
•
"Booting Commands" chapter of the Cisco IOS Configuration Fundamentals Command Reference
•
Cisco IOS Configuration Fundamentals and Network Management Configuration Guide
Troubleshooting Crashes and Hangs (stack, context, frame, sysret, meminfo)
This section lists and describes some ROM monitor commands that can be used to troubleshoot router crashes and hangs.
Most ROM monitor debug commands are functional only when the router crashes or hangs. If you enter a debug command when crash information is not available, the following error message appears:
"xxx: kernel context state is invalid, can not proceed."The ROM monitor commands in this section are all optional and can be entered in any order.
Router Crashes
A router or system crash is a situation in which the system detects an unrecoverable error and restarts itself. The errors that cause crashes are typically detected by processor hardware, which automatically branches to special error-handling code in the ROM monitor. The ROM monitor identifies the error, prints a message, saves information about the failure, and restarts the system. For detailed information about troubleshooting crashes, see the Troubleshooting Router Crashes and Understanding Software-forced Crashes tech notes.
Router Hangs
A router or system hang is a situation in which the system does not respond to input at the console port or to queries sent from the network, such as Telnet and Simple Network Management Protocol (SNMP).
Router hangs occur when:
•
The console does not respond
•
Traffic does not pass through the router
Router hangs are discussed in detail in the Troubleshooting Router Hangs tech note.
ROM Monitor Console Communication Failure
Under certain misconfiguration situations, it can be impossible to establish a console connection with the router due to a speed mismatch or other incompatibility. The most obvious symptom is erroneous characters in the console display.
If a ROM monitor failure of this type occurs, you may need to change a jumper setting on the motherboard so that the router can boot for troubleshooting. Procedures for accessing the motherboard and jumper locations are described in the installation of internal components section of the hardware installation document for your router.
The jumper to be changed is DUART DFLT, which sets the console connection data rate to 9600 regardless of user configuration. The jumper forces the data rate to a known good value.
Restrictions
Do not manually reload or power-cycle the router unless reloading or power cycling is required for troubleshooting a router crash. The system reload or power-cycle can cause important information to be lost that is needed for determining the root cause of the problem.
SUMMARY STEPS
1.
stack
or
k2.
context
3.
frame [number]
4.
sysret
5.
meminfo
DETAILED STEPS
Command or Action PurposeStep 1
stack
or
k
Example:rommon > stack
(Optional) Obtains a stack trace.
•
For detailed information on how to effectively use this command in ROM monitor mode, see the Troubleshooting Router Hangs tech note.
Step 2
context
Example:rommon > context
(Optional) Displays the CPU context at the time of the fault.
•
If it is available, the context from kernel mode and process mode of a loaded image is displayed.
Step 3
frame [number]
Example:rommon > frame 4
(Optional) Displays an entire individual stack frame.
•
The default is 0 (zero), which is the most recent frame.
Step 4
sysret
Example:rommon > sysret
(Optional) Displays return information from the last booted system image.
•
The return information includes the reason for terminating the image, a stack dump of up to eight frames, and, if an exception is involved, the address at which the exception occurred.
Step 5
meminfo [-l]
Example:rommon > meminfo
(Optional) Displays memory information, including:
•
Main memory size, starting address, and available range
•
Packet memory size
•
NVRAM size
Alternatively, using the meminfo -l command provides information on supported DRAM configurations for the router.
Examples
This section provides the following examples:
•
Sample Output for the stack ROM Monitor Command
•
Sample Output for the context ROM Monitor Command
•
Sample Output for the frame ROM Monitor Command
•
Sample Output for the sysret ROM Monitor Command
•
Sample Output for the meminfo ROM Monitor Command
Sample Output for the stack ROM Monitor Command
rommon 6> stackKernel Level Stack Trace:Initial SP = 0x642190b8, Initial PC = 0x607a0d44, RA = 0x61d839f8Frame 0 : FP= 0x642190b8, PC= 0x607a0d44, 0 bytesFrame 1 : FP= 0x642190b8, PC= 0x61d839f8, 24 bytesFrame 2 : FP= 0x642190d0, PC= 0x6079b6c4, 40 bytesFrame 3 : FP= 0x642190f8, PC= 0x6079ff70, 32 bytesFrame 4 : FP= 0x64219118, PC= 0x6079eaec, 0 bytesProcess Level Stack Trace:Initial SP = 0x64049cb0, Initial PC = 0x60e3b7f4, RA = 0x60e36fa8Frame 0 : FP= 0x64049cb0, PC= 0x60e3b7f4, 24 bytesFrame 1 : FP= 0x64049cc8, PC= 0x60e36fa8, 24 bytesFrame 2 : FP= 0x64049ce0, PC= 0x607a5800, 432 bytesFrame 3 : FP= 0x64049e90, PC= 0x607a8988, 56 bytesFrame 4 : FP= 0x64049ec8, PC= 0x64049f14, 0 bytesSample Output for the context ROM Monitor Command
rommon 7> contextKernel Level Context:Reg MSW LSW | Reg MSW LSW------ ---------- ---------- | ----- ---------- ----------zero : 00000000 00000000 | s0 : 00000000 34018001AT : 00000000 24100000 | s1 : 00000000 00000001v0 : 00000000 00000003 | s2 : 00000000 00000003v1 : 00000000 00000000 | s3 : 00000000 00000000a0 : 00000000 0000002b | s4 : 00000000 64219118a1 : 00000000 00000003 | s5 : 00000000 62ad0000a2 : 00000000 00000000 | s6 : 00000000 63e10000a3 : 00000000 64219118 | s7 : 00000000 63e10000t0 : 00000000 00070808 | t8 : ffffffff e7400884t1 : 00000000 00000000 | t9 : 00000000 00000000t2 : 00000000 63e10000 | k0 : 00000000 00000000t3 : 00000000 34018001 | k1 : 00000000 63ab871ct4 : ffffffff ffff80fd | gp : 00000000 63c1c2d8t5 : ffffffff fffffffe | sp : 00000000 642190b8t6 : 00000000 3401ff02 | s8 : 00000000 6429274ct7 : 00000000 6408d464 | ra : 00000000 61d839f8HI : ffffffff e57fce22 | LO : ffffffff ea545255EPC : 00000000 607a0d44 | ErrPC : ffffffff bfc05f2cStat : 34018002 | Cause : 00000020Process Level Context:Reg MSW LSW | Reg MSW LSW------ ---------- ---------- | ----- ---------- ----------zero : 00000000 00000000 | s0 : 00000000 6401a6f4AT : 00000000 63e10000 | s1 : 00000000 00000000v0 : 00000000 00000000 | s2 : 00000000 64049cf0v1 : 00000000 00000440 | s3 : 00000000 63360000a0 : 00000000 00000000 | s4 : 00000000 63360000a1 : 00000000 00070804 | s5 : 00000000 62ad0000a2 : 00000000 00000000 | s6 : 00000000 63e10000a3 : 00000000 00000000 | s7 : 00000000 63e10000t0 : 00000000 00000000 | t8 : ffffffff e7400884t1 : 00000000 64928378 | t9 : 00000000 00000000t2 : 00000000 00000001 | k0 : 00000000 644822e8t3 : ffffffff ffff00ff | k1 : 00000000 61d86d84t4 : 00000000 6079eee0 | gp : 00000000 63c1c2d8t5 : 00000000 00000001 | sp : 00000000 64049cb0t6 : 00000000 00000000 | s8 : 00000000 6429274ct7 : 00000000 6408d464 | ra : 00000000 60e36fa8HI : ffffffff e57fce22 | LO : ffffffff ea545255EPC : 00000000 60e3b7f4 | ErrPC : ffffffff ffffffffStat : 3401ff03 | Cause : ffffffffSample Output for the frame ROM Monitor Command
rommon 6 > frame 2Stack Frame 2, SP = 0x642190d0, Size = 40 bytes[0x642190d0 : sp + 0x000] = 0xffffffff[0x642190d4 : sp + 0x004] = 0xbfc05f2c[0x642190d8 : sp + 0x008] = 0xffffffff[0x642190dc : sp + 0x00c] = 0xffffffff[0x642190e0 : sp + 0x010] = 0x6401a6f4[0x642190e4 : sp + 0x014] = 0x00000000[0x642190e8 : sp + 0x018] = 0x64049cf0[0x642190ec : sp + 0x01c] = 0x63360000[0x642190f0 : sp + 0x020] = 0x63360000[0x642190f4 : sp + 0x024] = 0x6079ff70Sample Output for the sysret ROM Monitor Command
rommon 8> sysretSystem Return Info:count: 19, reason: user breakpc:0x801111b0, error address: 0x801111b0Stack Trace:FP: 0x80005ea8, PC: 0x801111b0FP: 0x80005eb4, PC: 0x80113694FP: 0x80005f74, PC: 0x8010eb44FP: 0x80005f9c, PC: 0x80008118FP: 0x80005fac, PC: 0x80008064FP: 0x80005fc4, PC: 0xfff03d70FP: 0x80005ffc, PC: 0x00000000FP: 0x00000000, PC: 0x00000000Sample Output for the meminfo ROM Monitor Command
rommon 3> meminfo-------------------------------------------------Current Memory configuration is:Onboard SDRAM: Size = 128 MB : Start Addr = 0x10000000-----Bank 0 128 MB-----Bank 1 0 MBDimm 0: Size = 256 MB : Start Addr = 0x00000000-----Bank 0 128 MB-----Bank 1 128 MB-------------------------------------------------Main memory size: 384 MB in 64 bit mode.Available main memory starts at 0xa0015000, size 393132KBIO (packet) memory size: 10 percent of main memory.NVRAM size: 191KBYou can also use the meminfo -l command to show the supported DRAM configurations for the router. The following is sample output for the command:
rommon 4 > meminfo -l
The following 64 bit memory configs are supported:-------------------------------------------------Onboard SDRAM DIMM SOCKET 0 TOTAL MEMORYBank 0 Bank1 Bank 0 Bank 1------------- ------------- ------------128 MB 0 MB 0 MB 0 MB 128 MB128 MB 0 MB 64 MB 0 MB 192 MB128 MB 0 MB 64 MB 64 MB 256 MB128 MB 0 MB 128 MB 0 MB 256 MB128 MB 0 MB 128 MB 128 MB 384 MB128 MB 0 MB 256 MB 0 MB 384 MBTroubleshooting Tips
See the following tech notes:
•
Troubleshooting Router Crashes
•
Understanding Software-forced Crashes
Exiting ROM Monitor Mode
This section describes how to exit ROM monitor mode and enter the Cisco IOS command-line interface (CLI). The method that you use to exit ROM monitor mode depends on how your router entered ROM monitor mode:
•
If you reload the router and enter the Break key sequence to enter ROM monitor mode when the router would otherwise have booted the system image, you can exit ROM monitor mode by doing either of the following:
–
Enter the i command or the reset command, which restarts the booting process and loads the system image.
–
Enter the cont command, which continues the booting process and loads the system image.
•
If your router entered ROM monitor mode because it could not locate and load the system image, perform the steps in the following procedure.
SUMMARY STEPS
1.
dir flash: [directory]
2.
boot flash: [directory] [filename]
or
boot filename tftpserver
or
boot [filename]DETAILED STEPS
Command or Action PurposeStep 1
dir flash:[directory]
Example:rommon > dir flash:
Displays a list of the files and directories in flash memory.
•
Locate the system image that you want the router to load.
•
If the system image is not in flash memory, use the second or third option in Step 2.
Step 2
boot flash:[directory] [filename]
or
boot filename tftpserver
or
boot [filename]
Example:ROMMON > boot flash:myimage
Example:ROMMON > boot someimage 172.16.30.40
Example:ROMMON > boot
In order, the examples here direct the router to:
•
Boot the first image or a specified image in flash memory.
•
Boot the specified image over the network from the specified TFTP server (hostname or IP address).
•
Boot from the boothelper image because it does not recognize the device ID. This form of the command is used to netboot a specified image.
You can override the default boothelper image setting by setting the BOOTLDR Monitor environment variable to point to another image. Any system image can be used for this purpose.
Note
Options to the boot command are -x (load image but do not execute) and -v (verbose).
Examples
Sample Output for the dir flash: Command in ROM Monitor mode
rommon > dir flash:File size Checksum File name2229799 bytes (0x220627) 0x469e c2801-j-m2.113-4TWhat to Do Next
Now that you have a system image running on your router, configure the router to load the correct image at the next system reload or power-cycle. See the following documents:
•
"Booting Commands" chapter of the Cisco IOS Configuration Fundamentals Command Reference
•
Cisco IOS Configuration Fundamentals and Network Management Configuration Guide
Additional References
The following sections provide references related to using the ROM monitor.
Related Documents
Related Topic Document TitleConnecting your PC to the router console port
•
Quick start guide for your router
•
Hardware installation guide for your router
Break key sequence combinations for entering ROM monitor mode within the first 60 seconds of rebooting the router
Standard Break Key Sequence Combinations During Password Recovery
Upgrading the ROM monitor
ROM Monitor Download Procedures for Cisco 2691, Cisco, 3631, Cisco 3725, and Cisco 3745 Routers
Note
These procedures also apply to Cisco 1841 series, Cisco 2800 series, and Cisco 3800 series routers.
Using the boot image (Rx-boot) to recover or upgrade the system image
Booting and configuration register commands
Cisco IOS Configuration Fundamentals Command Reference
Loading and maintaining system images; rebooting
Cisco IOS Configuration Fundamentals and Network Management Configuration Guide
Choosing and downloading system images
Software Center at
Console download (xmodem)
Router crashes
Troubleshooting Router Crashes
Router hangs
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