826 with lost EPROM cookie information

Unanswered Question
Apr 9th, 2006
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I am having trouble with a Cisco 826. It has lost it's EPROM cookie information, and now it won't boot.

Cisco TAC doesn't want to help me, since I have no service contract.


Does anyone know how to restore this?

I found the following web page that describes exactly this problem:

http://www.tech-recipes.com/cisco_router_tips982.html

But unfortunately the described command "COOKIE" doesn't work. And, the page refers to 827, not 826, and there may be differences between those two.


So, I need three things:


1) Anyone having a Cisco 826, able to go to rommon, getting correct cookie values via the "cookie" command and sending me the output.

Warning: This will interrupt your service, so don't do that in a production environment.


2) A way to determine device-specific values like mac address, processor board ID, etc. Maybe these values can be derived from the serial number? Do they matter at all? (I think no.)


3) A working rommon command allowing me to enter these cookie values manually.


Below is cold boot output from the console, plus output from the "cookie" rommon command.


I would greatly appreciate any help on this.


Regards,

Patrick Berchtold

(currently running on ISDN...)


-----

System Bootstrap, Version 12.2(4r)XM1, RELEASE SOFTWARE (fc1)

TAC Support: http://www.cisco.com/tac

Copyright (c) 2001 by cisco Systems, Inc.

WARNING: Cookie information is corrupt

C800/SOHO series (Board ID: 13-0) platform with 32768 Kbytes of main

memory


loadprog: error - Invalid image for platform

e_machine = 62, cpu_type = 0

boot: cannot load "flash:"ú

System Bootstrap, Version 12.2(4r)XM1, RELEASE SOFTWARE (fc1)

TAC Support: http://www.cisco.com/tac

Copyright (c) 2001 by cisco Systems, Inc.

WARNING: Cookie information is corrupt

C800/SOHO series (Board ID: 13-0) platform with 32768 Kbytes of main

memory


loadprog: error - Invalid image for platform

e_machine = 62, cpu_type = 0

boot: cannot load "flash:"


System Bootstrap, Version 12.2(4r)XM1, RELEASE SOFTWARE (fc1)

TAC Support: http://www.cisco.com/tac

Copyright (c) 2001 by cisco Systems, Inc.

WARNING: Cookie information is corrupt

C800/SOHO series (Board ID: 13-0) platform with 32768 Kbytes of main

memory


rommon 1 > cookie

WARNING: Cookie information is corrupt


cookie:

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

rommon 2 >

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answanso Tue, 04/18/2006 - 12:37
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  • Cisco Employee,

You have to use the priv command in ROMMON to get to where you can enter the cookie output.


rommon 14 > priv

Password:

You now have access to the full set of monitor commands.

Warning: some commands will allow you to destroy your

configuration and/or system images and could render

the machine unbootable.

rommon 15 >


Since the cookie is set to all zero's the password should be 0000.


HTH

Anthony


ankurbhasin Tue, 04/18/2006 - 22:29
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  • Red, 2250 points or more

Hi Anthony,


Can you please help person name Mujeeb in the post he had posted for same issue in lan,switching and routing forum


http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.1ddafd7c


I tried helping him but he is now stuck up to place where I am cluless.


Will appreciate you help!!


Regards,


Ankur

pberchtold Wed, 04/19/2006 - 07:06
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That may solve part 3 of my problem.


But your answer also implies a new question: How is the "priv" password if cookie is not set to all zeros?


In other words: The password must be stored in the cookie somehow. If I enter new cookie values and later find out that they are not correct/working/whatever, I'll have to go back to "priv" rommon mode. Thus I have to know how the "priv" password is calculated from the cookie value.


Any guesses on that?


However, thank you for your help anyway.


Regards,

Patrick

answanso Wed, 04/19/2006 - 10:25
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  • Cisco Employee,

I know how to calculate the priv password, but I can not share that information for obvious reasons. The priv password for all zeros will be "0000". If you have issues after that, post the new cookie and I will try to help you out with the new password.


HTH

Anthony

pberchtold Wed, 04/19/2006 - 21:58
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Anthony,


Thanks for your offer to help. I have already found out how to derive the password from the current cookie. Since this seems to be some sort of cisco secret, i won't post it here. Anyone who really wants to know it will find it out themselves.

Most of my other questions are also answered, e.g. how the processor board id is encoded in the cookie (not that hard;-)

Some other points are still open, but I have seen that some values may be guessed, or at least can be copied from other routers.

I have been able to fix the router, it is up and running again.


Thank you anyway, your help was very valuable for me.


Patrick

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