How To Install Ios In Cisco Router In Rommon Mode
Table Of Contents
ROM Monitor
Entering the ROM Monitor
ROM Monitor Commands
Command Descriptions
Disaster Recovery with TFTP Download
TFTP Download Command Variables
Required Variables
Optional Variables
Using the TFTP Download Command
Configuration Register
Irresolute the Configuration Register Manually
Changing the Configuration Annals Using Prompts
Console Download
Control Clarification
Error Reporting
Debug Commands
Exiting the ROM Monitor
ROM Monitor
The ROM monitor firmware runs when the router is powered upwardly or reset. The firmware helps to initialize the processor hardware and boot the operating system software. You can apply the ROM monitor to perform sure configuration tasks, such as recovering a lost countersign or downloading software over the console port. If there is no Cisco IOS software image loaded on the router, the ROM monitor runs the router.
This appendix contains the following sections:
•
Entering the ROM Monitor
•ROM Monitor Commands
•Command Descriptions
•Disaster Recovery with TFTP Download
•Configuration Annals
•Console Download
•Debug Commands
•Exiting the ROM Monitor
Entering the ROM Monitor
To utilise the ROM monitor, you lot must be using a final or PC that is continued to the router over the panel port.
Perform these steps to configure the router to kick up in ROM monitor way the next time it is rebooted.
| Control | Purpose | |
|---|---|---|
| Step 1 | enable | Enters privileged EXEC mode. Enter your password if prompted. |
| Step 2 | configure terminal | Enters global configuration mode. |
| Step 3 | config-reg 0x0 | Resets the configuration annals. |
| Step iv | exit | Exits global configuration mode. |
| Footstep five | reload | Reboots the router with the new configuration register value. The router remains in ROM monitor and does not kick the Cisco IOS software. As long as the configuration value is 0x0, you must manually kicking the operating organisation from the panel. See the boot control in the "Command Descriptions" section in this appendix. After the router reboots, information technology is in ROM monitor mode. The number in the prompt increments with each new line. Annotation |
Timesaver Suspension (system interrupt) is always enabled for lx seconds afterward the router reboots, regardless of whether it is set to on or off in the configuration annals. During this 60-second window, y'all can break to the ROM monitor prompt past pressing the Suspension key.
ROM Monitor Commands
Enter ? or help at the ROM monitor prompt to display a listing of bachelor commands and options, as follows:
alias set up and display aliases command
boot kicking up an external process
break gear up/show/articulate the breakpoint
confreg configuration annals utility
cont go along executing a downloaded image
context brandish the context of a loaded prototype
cookie display contents of cookie PROM in hex
copy Copy a file-copy [-b <buffer_size>] <src_file> <dst_file>
delete Delete file(due south)-delete <filenames ...>
dir List files in directories-dir <directory>
dis brandish instruction stream
dnld serial download a programme module
format Format a filesystem-format <filessystem>
frame print out a selected stack frame
fsck Check filesystem consistency-fsck <filesystem>
help monitor builtin command help
history monitor command history
meminfo principal memory information
mkdir Create dir(s)-mkdir <dirnames ...>
more than Concatenate (type) file(s)-cat <filenames ...>
rename Rename a file-rename <old_name> <new_name>
repeat repeat a monitor command
set brandish the monitor variables
stack produce a stack trace
sync write monitor environment to NVRAM
sysret print out info from last system return
tftpdnld tftp epitome download
unset unset a monitor variable
xmodem x/ymodem image download
Commands are example sensitive. You can halt whatever command past pressing the Break key on a terminal. If you are using a PC, most concluding emulation programs halt a command when you press the Ctrl and the Break keys at the same time. If y'all are using some other blazon of final emulator or terminal emulation software, see the documentation for that product for information on how to transport a Break command.
Control Descriptions
Tabular array C-1 describes the most ordinarily used ROM monitor commands.
| Command | Description |
|---|---|
| help or ? | Displays a summary of all available ROM monitor commands. |
| -? | Displays information nearly command syntax; for case: rommon xvi > dis -? usage : dis [addr] [length] The output for this command is slightly different for the xmodem download command: rommon xi > xmodem -? xmodem: illegal option -- ? usage: xmodem [-cyrxu] <destination filename> -c CRC-xvi -y ymodem-batch protocol -r copy image to dram for launch -x do non launch on download completion -u upgrade ROMMON, Arrangement will reboot after upgrade |
| reset or i | Resets and initializes the router, like to a ability upwards. |
| 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) |
| kicking commands | For more than information nearly the ROM monitor kick commands, see the Cisco IOS Configuration Fundamentals and Network Direction Guide. |
| b | Boots the offset image in flash retention. |
| b wink: [filename] | Attempts to kick the image direct from the outset partition of flash memory. If yous practice not enter a filename, this command will kicking this first paradigm in flash memory. |
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). Withal, if the router is unable to boot Cisco IOS software, you tin can load new software while in ROM monitor style.
This section describes how to load a Cisco IOS software image from a remote TFTP server to the router flash retentivity. Use the tftpdnld control but for disaster recovery, because it erases all existing data in flash memory before downloading a new software prototype to the router.
TFTP Download Control Variables
This section describes the system variables that can be set in ROM monitor fashion and that are used during the TFTP download process. There are both required variables and optional variables.
Note The commands described in this section are case sensitive and must be entered exactly as shown.
Required Variables
These variables must exist set with these commands before you lot employ the tftpdnld command:
| Variable | Command |
| IP address of the router. | IP_ADDRESS= ip_address |
| Subnet mask of the router. | IP_SUBNET_MASK= ip_address |
| IP address of the default gateway of the router. | DEFAULT_GATEWAY= ip_address |
| IP accost of the TFTP server from which the software volition exist downloaded. | TFTP_SERVER= ip_address |
| Proper noun of the file that will be downloaded to the router. | TFTP_FILE= filename |
Optional Variables
These variables can exist set up 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 signal file download progress. This is the default setting. 2—Detailed progress is displayed during the file download process; for example: • • • • | TFTP_VERBOSE= setting |
| Number of times the router attempts ARP and TFTP download. The default is 7. | TFTP_RETRY_COUNT= retry_times |
| Length of time, in seconds, before the download procedure times out. The default is | TFTP_TIMEOUT= time |
| Whether or non the router performs a checksum test on the downloaded epitome: one—Checksum test is performed. 0—No checksum test is performed. | TFTP_CHECKSUM= setting |
Using the TFTP Download Command
Perform these steps in ROM monitor mode to download a file through TFTP.
Stride 1 Utilize the appropriate commands to enter all the required variables and whatever optional variables described in preceding sections.
Stride ii Enter the tftpdnld command as follows:
Note The -r variable is optional. Entering this variable downloads and boots the new software just does not relieve the software to flash memory. You tin then use the epitome that is in flash retentiveness the side by side time you enter the reload control.
You will run into output like to the following:
IP_SUBNET_MASK: 255.255.0.0
DEFAULT_GATEWAY: ten.3.0.1
TFTP_SERVER: 192.168.254.254
TFTP_FILE: c870-advsecurityk9-mz
Do y'all wish to continue? y/n: [due north]:
Step 3 If yous are sure that you desire to continue, enter y in response to the question in the output:
Do you wish to continue? y/northward: [n]:y
The router begins to download the new file.
If you mistakenly entered yes, you lot tin can enter Ctrl-C or Break to cease the transfer before the flash memory is erased.
Configuration Register
The virtual configuration register is in nonvolatile RAM (NVRAM) and has the same functionality equally other Cisco routers. You can view or alter the virtual configuration register from either the ROM monitor or the operating arrangement software. Within the ROM monitor, you can change the configuration register by inbound the register value in hexadecimal format, or by allowing the ROM monitor to prompt you for the setting of each fleck.
Changing the Configuration Register Manually
To change the virtual configuration register from the ROM monitor manually, enter the confreg command followed by the new value of the register in hexadecimal format, equally shown in the post-obit example:
rommon i > confreg 0x2101
You must reset or power bike for new config to accept effect
The value is always interpreted as hexadecimal. The new virtual configuration register value is written into NVRAM merely does not take outcome until you reset or reboot the router.
Changing the Configuration Register Using Prompts
Entering the confreg command without an argument displays the contents of the virtual configuration register and a prompt to alter the contents by describing the significant of each scrap.
In either case, the new virtual configuration register value is written into NVRAM simply does not take effect until yous reset or reboot the router.
The following display shows an example of entering the confreg command:
exercise you wish to change the configuration? y/n [due north]: y
enable "diagnostic mode"? y/n [n]: y
enable "employ net in IP bcast address"? y/n [due north]:
enable "load rom after netboot fails"? y/n [due north]:
enable "utilise all zero circulate"? y/n [n]:
enable "interruption/abort has effect"? y/n [n]:
enable "ignore system config info"? y/n [n]:
alter console baud charge per unit? y/n [n]: y
enter rate: 0 = 9600, 1 = 4800, 2 = 1200, 3 = 2400 [0]: 0
modify the boot characteristics? y/n [n]: y
i = the kicking helper epitome
do you wish to change the configuration? y/n [n]:
You must reset or power bike for new config to accept effect
Console Download
You tin can use console download, a ROM monitor function, to download either a software image or a configuration file over the router console port. After download, the file is either saved to the mini-flash retentivity module or to primary memory for execution (image files only).
Use console download when y'all do non have access to a TFTP server.
Note If y'all want to download a software prototype or a configuration file to the router over the console port, you must use the ROM monitor dnld command.
Notation If y'all are using a PC to download a Cisco IOS image over the router panel port at 115,200 bps, ensure that the PC series 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 bps or less when downloading a Cisco IOS paradigm over the console port.
Command Description
The following are the syntax and descriptions for the xmodem panel download command:
xmodem [ -cyrx ] destination_file_name
| c | Optional. Performs the download using 16-bit cyclic redundancy check (CRC-sixteen) error checking to validate packets. Default is 8-fleck CRC. |
| y | Optional. Sets the router to perform the download using Ymodem protocol. The default is Xmodem protocol. The protocols differ as follows: • • |
| r | Optional. Image is loaded into DRAM for execution. The default is to load the paradigm into flash retentiveness. |
| 10 | Optional. Epitome is loaded into DRAM without beingness executed. |
| destination_file_name | Proper name of the system image file or the organisation configuration file. In order for the router to recognize it, the proper name of the configuration file must exist router_confg. |
Follow these steps to run Xmodem:
Step 1 Move the image file to the local drive where Xmodem volition execute.
Step 2 Enter the xmodem command.
Mistake Reporting
Because the ROM monitor console download uses the console to perform the data transfer, when an fault occurs during a information transfer, error messages are merely displayed on the console once the information transfer is terminated.
If you lot accept changed the baud rate from the default rate, the fault message is followed by a bulletin 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 Cisco IOS software has crashed or is halted. If you enter a debugging command and Cisco IOS crash information is not available, you come across the following mistake bulletin:
"xxx: kernel context country is invalid, can non proceed."
The following are ROM monitor debugging commands:
• stack or m—Produces a stack trace; for case:
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
• context—Displays processor context; for example:
CPU context of the most recent exception:
PC = 0x801111b0 MSR = 0x00009032 CR = 0x53000035 LR = 0x80113694
CTR = 0x801065e4 XER = 0xa0006d36 DAR = 0xffffffff DSISR = 0xffffffff
December = 0xffffffff TBU = 0xffffffff TBL = 0xffffffff IMMR = 0xffffffff
R0 = 0x00000000 R1 = 0x80005ea8 R2 = 0xffffffff R3 = 0x00000000
R4 = 0x8fab0d76 R5 = 0x80657d00 R6 = 0x80570000 R7 = 0x80570000
R8 = 0x00000000 R9 = 0x80570000 R10 = 0x0000954c R11 = 0x00000000
R12 = 0x00000080 R13 = 0xffffffff R14 = 0xffffffff R15 = 0xffffffff
R16 = 0xffffffff R17 = 0xffffffff R18 = 0xffffffff R19 = 0xffffffff
R20 = 0xffffffff R21 = 0xffffffff R22 = 0xffffffff R23 = 0xffffffff
R24 = 0xffffffff R25 = 0xffffffff R26 = 0xffffffff R27 = 0xffffffff
R28 = 0xffffffff R29 = 0xffffffff R30 = 0xffffffff R31 = 0xffffffff
• frame—Displays an individual stack frame.
• sysret—Displays return data from the last booted system epitome. This data includes the reason for terminating the prototype, a stack dump of upwardly to 8 frames, and, if an exception is involved, the address where the exception occurred; for example:
count: 19, reason: user suspension
pc:0x801111b0, error address: 0x801111b0
FP: 0x80005ea8, PC: 0x801111b0
FP: 0x80005eb4, PC: 0x80113694
FP: 0x80005f74, PC: 0x8010eb44
FP: 0x80005f9c, PC: 0x80008118
FP: 0x80005fac, PC: 0x80008064
FP: 0x80005fc4, PC: 0xfff03d70
FP: 0x80005ffc, PC: 0x00000000
FP: 0x00000000, PC: 0x00000000
• meminfo—Displays size in bytes, starting address, bachelor range of main retentiveness, the starting signal and size of parcel memory, and size of NVRAM; for instance:
Bachelor main memory starts at 0x10000, size 40896KB
IO (packet) memory size: v per centum of chief memory.
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 prototype from wink 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 wink memory:
rommon 1 > confreg 0x2101
Y'all must reset or power cycle for new config to take effect:
The router will boot the Cisco IOS image in flash memory. The configuration register will alter to 0x2101 the next time the router is reset or ability cycled.
Source: https://www.cisco.com/en/US/docs/routers/access/800/850/software/configuration/guide/rommon.html
Posted by: wrightwerighly.blogspot.com
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