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Cisco 1721 router problem

How can i exit from the rommon mode on cisco 1721 router

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  • raveesh Apr 14, 2008

    Dear team,

    i changed the register value as per your instruction ,but still the router in rommon mode ,i hope the problem with ios ,if the router dont have valid ios image how can load a valid ios image in to flash memory ?

    thanks and regards




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Does the router boot to rommon mode everytime you turn it on?

There are two reasons why the router could be booting to rommon mode

1. There isn't a valid ios image loaded in flash memory
2. The configuration register is set to a number that ends with '0'

Change the configuration register setting to a number that ends in '2'. (i.e. 0x2402)

You do this with the command: confreg 0x2402 <hit enter key> (in rommon mode)

Reboot the router and it will first search for boot system commands in the startup config, if none found it will boot to the first valid ios image in flash memory.

If there isn't a valid ios image in flash memory, the router will continue to boot to rommon.

Posted on Apr 13, 2008



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How do I reset the Cisco router password?

Perform these steps in order to recover your password:
  1. Either switch off or shut down the router.
  2. Remove the compact flash that is on the rear of the router. ...
  3. Switch on the router.
  4. Once the router is on Rommon mode, reinsert the compact flash.
  5. Type confreg 0x2142 at the rommon 1> prompt in order to boot from Flash.
  6. if you still confused, you can also visit Router-Switch, There's a lot of answer about network products, You can also seek artificial services here, they will be happy to help you.

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Confreg command

Try just typing confreg from rommon mode and going through the dialog.

Or from the CLI in configuration mode:

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Cisco IAD 2432-24FXS stuck in Rommon mode.

Is there a valid IOS image on the flash on the IAD? If it will only boot to ROMMON, also try issuing the "boot" command from the console prompt. If it then boots, you need to go into the configuration and set the boot election to auto-boot.

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Basically you will need to use TFTP to get the IOS back on. HERE is an article from Cisco that explains how to do it. I have done this before and even though it takes a while to reload the IOS (because in my case I had to use a serial connection at 9600 baud) it does work.

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Flash: CompactFlash not present I am getting above error when i power on a cisco 1841 router

Did you do anything to the compact flash, like try to format it and copy an image to it? Cisco routers are very picky about the formatting on the flash. It has to be formatted FAT16 and the image has to be the first file on the card.

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I m in rommon booting router version can i exit from rommon?help me.

you need to change the config register back to 0x2102.
type "?" and find the command to change startup settings, go through the list (I'm working from memory here, sorry) and make sure it is NOT ignoring startup settings. There may be a way to edit the config register value directly, can't recall.

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I have a problem with a cisco catalyst 2948G-L3. A have erase of mistake the bootflash. I have tried in some way to download a new IOS, i have the IOS bu i cannot download it in the flash because the...

Two ways to do that are xmodem (slow) or Tftp from rommon mode. (fast)
Place the IOS image in your tftp server directory and start tftp server.
Then enter the following in the switch exactly as below as all are case sensative:
rommon 1>
rommon 2>
rommon 3>
rommon 4>
rommon 5> TFTP_FILE=full file name of ios as it reads
rommon 6> TFTP_CHECKSUM=0
this one is in lower case
rommon 7> tftpdnld

If you dont have a tftp server below is a link to a free one

You will need the .bin IOS image for this and not the .tar file. The .tar file contains router cluster management files that you must issue the archive tar command to load all of the files. Can do that if needed after router is back online.

P.S.: If this information was helpful, please rate this solution.

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normally if you forget the password with cisco, boot the router in rommon mode and change the registry to 0x2142 and reboot the router and change the password and change back the registry to 0x2102.

did you tried this all ...can u explain more about the same

Feb 09, 2009 | Cisco 2610XM Router

1 Answer

Bootup Router and then nothing

Your router is in the wrong mode. You need to change this by changing the conf-register to 0x2102

at the rommon prompt type in

config-reg 0x2102


If there are any errors you can get the correct syntax by typing ? at the rommon prompt the line number will go up on every line.

The way to get into rommon mode is by pressing the break key from Hyperterminal as the router is rebooting. So make sure you don't do this by accident. If you do just reboot by power cycling.

Your Startup Config should be unchanged, but you need to be very careful what you do in rommon mode it is easy to blat stuff.

Any changes you make once you get into the command (enable) mode should be saved by
copy running-config startup-config

Any problems just let me know.

good feed back would be much appreciated.


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Cisco router 857

hey you are saying that you want to configure the router,, but rommon mode is for breaking the u forget the password of the router......can you explain why u need to log in through rommon mode

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