Cisco 1842 rommon problem - Cisco (1841) Router (cisco1841)

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.

With the set command.

Example:
rommon > set
PS1=rommon ! >
IP_ADDRESS=172.18.16.76
IP_SUBNET_MASK=255.255.255.192 DEFAULT_GATEWAY=172.18.16.65
TFTP_SERVER=172.18.16.2
TFTP_FILE=c2600-i-mz.bin

Alternatively you can XMODEM an image on there. However, that takes a long time, even if you increase your baud rate.

Also, on 2800 series routers you can put the image on a USB flash drive. However, the drive must be formatted as FAT and the partition size cannot be larger than 256 MB. This might work for an 1841.

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.

It looks like the IOS is bad or not not there.
You need to instal a new IOS onto the switch.


For more help during installation you can refer
http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a00800949c3.shtml#cat4k

have a look at http://cio.cisco.com

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> IP_ADDRESS=xxx.xxx.xxx.xxx
rommon 2> IP_SUBNET_MASK=xxx.xxx.xxx.xxx
rommon 3> DEFAULT_GATEWAY=xxx.xxx.xxx.xxx
rommon 4> TFTP_SERVER=xxx.xxx.xxx.xxx
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
http://www.solarwinds.net/Tools/Free_tools/TFTP_Server/

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.

Hi,
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

reboot

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.

Carrie

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

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.