Cisco Router 800 Series Software Configuration Guide
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B-5 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 Appendix B ROM Monitor ROM Monitor Commands Step 7Enter y to start the download. Successive exclamation points (!!!!!!) indicate that the download is occurring. The router reboots when the download is complete. Updating in Cisco IOS EXEC Mode Step 1Download the ROMMON image from CCO, and place it on your TFTP server. Step 2In EXEC mode, save the current configuration, using the copy running-config startup-config command. Step 3Enter the copy tftp rommon command, and answer the prompts. Replace the variables shown in the following example with the correct values for your router: 820-2#copy tftp:rommon: Address or name of remote host []? IP_address_of_remote_host Source filename []? rommon_image_source_file_name Destination filename [rommon]? rommon_image_destination_file_name ROM Monitor Commands 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
Appendix B ROM Monitor Command Descriptions B-6 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 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. Command Descriptions Ta b l e B - 1 describes the most commonly used ROM monitor commands. Table B-1 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 [-cyrxu] -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
B-7 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 Appendix B ROM Monitor Disaster Recovery with TFTP Download Disaster Recovery with TFTP Download 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. tftpdnld 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. reset or iResets and initializes the router, similar to a power up. devLists boot device identifications on the router; for example: rommon 10> dev Devices in device table: id name flash: flash dir device:Lists the files on the named device; flash, for example: rommon 4 > dir flash: File size Checksum File name 2835276 bytes (0x2b434c) 0x2073 c806-oy6-mz boot commands For more information about the ROM monitor boot commands, refer to the Cisco IOS Configuration Guide and the Cisco IOS Command Reference. bBoots 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. Table B-1 Most Commonly Used ROM Monitor Commands (continued) Command Description
Appendix B ROM Monitor Disaster Recovery with TFTP Download B-8 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 NoteThe commands described in this section are case sensitive and must be entered exactly as shown. Required 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 routerIP_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
B-9 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 Appendix B ROM Monitor Disaster Recovery with TFTP Download Optional Variables The following variables should 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:01TFTP_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 7,200 seconds (120 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
Appendix B ROM Monitor Using the TFTP Download Command Without Writing the Image to Flash Memory B-10 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 Using the TFTP Download Command Without Writing the Image to Flash Memory Follow the steps below to do download new file in ROM monitor mode. Step 1Use the appropriate commands to enter all the required variables and any optional variables described earlier in this section. Step 2Enter the tftpdnld command as follows: rommon 1 > tftpdnld [-r] NoteThe -r variable is optional. Entering this variable downloads and boots the new software but does not save the software to Flash memory. You can then use the image that is in Flash memory the next time you enter the reload command. 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: c806-sy-mz 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 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 The router begins to download the new file. Enter Ctrl-C or Break to stop the transfer before the Flash memory is erased.
B-11 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 Appendix B ROM Monitor Configuration Register Configuration Register 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. Within ROM monitor, you can change the configuration register by entering the register value in hexadecimal format, or by allowing the ROM monitor to prompt you for the setting of each bit. Changing the Configuration Register Manually To change the virtual configuration register from the ROM monitor manually, enter the command confreg followed by the new value of the register in hexadecimal, as shown in the following example: rommon 1 > confreg 0x2101 You must reset or power cycle for new config to take effect rommon 2 > The value is always interpreted as hexadecimal. The new virtual configuration register value is written into NVRAM but does not take effect until you reset or reboot the router. Changing the Configuration Register Using Prompts 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
Appendix B ROM Monitor Console Download B-12 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 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 Console Download You can use console download, a ROM monitor function, to download over the router console port either a software image or a configuration file. Make sure that the Cisco IOS image is in the same PC where you are to perform this function. 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 TFTP server. NoteIf you want to download a software image or a configuration file to the router over the console port, you must use the ROM monitor command.
B-13 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 Appendix B ROM Monitor Console Download Note If you are using a PC to download a Cisco IOS image over the router console port at 115,200 bps, ensure that the PC serial port is using a 16550 universal asynchronous transmitter/receiver (UART). If the PC serial port is not using a 16550 UART, we recommend using a speed of 38,400 or less when downloading a Cisco IOS image over the console port. 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 download using Ymodem protocol. Default is Xmodem protocol. The protocols differ as follows: Xmodem supports a 128-block transfer size. Ymodem supports a 1024-block transfer size. Ymodem uses CRC-16 error checking to validate each packet. Depending on the device that the software is being downloaded from, this function might not be supported by Xmodem. rOptional. Image is loaded into DRAM for execution. Default is to load the image into Flash memory. xOptional. Image is loaded into DRAM without being executed. destination_ file_nameThe 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.
Appendix B ROM Monitor Debug Commands B-14 Cisco 800 Series Routers Software Configuration Guide 78-5372-06 Follow the steps below to run Xmodem: Step 1Move the image file to the local drive where the Xmodem will execute. Step 2Enter the xmodem command. Error Reporting Because the ROM monitor console download uses the console to perform the data transfer, error messages are displayed on the console only 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. Debug Commands Most ROM monitor debugging commands are functional only when the Cisco IOS software has crashed or is halted. If you enter a debugging command and Cisco IOS crash information is not available, you see the following error message: xxx: kernel context state is invalid, cannot proceed. The following are ROM monitor debugging commands: stack or k—produces a stack trace; for example: 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