Password recovery for 3640

Unanswered Question
Feb 1st, 2007

Hi, I have 3640 with config register 0x3922, please help me to reset my enable secret password.

I have this problem too.
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Overall Rating: 3 (1 ratings)
kyawzawhtut Thu, 02/01/2007 - 18:50

Try these method. Make sure you have backup config as all of them destroy the startup config.

1. Routers that have nonvolatile RAM (NVRAM) chips can be removed and reseated. The NVRAM is implemented with battery-backed up static RAM (SRAM). If you remove the SRAM, the contents of NVRAM are erased as well as the no service password-recovery configuration. Be sure to use proper anti-static procedures when you handle the NVRAM. Some of these routers are 3640 and 3660.

2. Other routers, such as the 1700, 2600, and 3620, use an electrically erasable programmable read-only memory (EEPROM) in order to hold the configuration. The EEPROM does not erase when you remove it.

3. Another method is to reload or boot the router with console access, and press CTRL-BREAK within five to ten seconds of the Cisco IOS software image decompressing or roughly when the "Image text-base:... " part of the banner begins. You are then prompted to reset the router to factory default (erase start-up configuration).

Rate if help.


thelion80 Fri, 02/02/2007 - 12:38


i have the same problem,

i tried with CTRL+Break, and after reset the router won't start up, in Hyper T. I had this characters JJJJJJJJ... instead of ###########... when the router is booting up.

I have a cisco router 2600

Can anyone help me ?

thanks in advance!

smothuku Fri, 02/02/2007 - 20:02


You are getting junk characters because of different baud rate configured on the router and you are trying to access the router using deafult values of hyper terminal.

Try to change the Baud rate of hyperterminal form least value to Max. value and at one particular point you can access the router.You willn't find these junk characters.Router will boot normally and if you want to recover the password then follow the step mentioned in the doc's which i already posted.



smothuku Thu, 02/01/2007 - 19:49

HI ,

Please follow the steps mentioned in the following link for recovring the password.

Below link is very useful for recovring passwords of routers and switches.

Hope it helps you.



adnan.zafar Thu, 02/01/2007 - 22:46


Just restart the router and when its start press Clt+Pausebreak Keys once

then your router will become on rommon mode like this


Now just write this commanda

rommon>confreg 0x42 or 0x2102



Now your router will restart and it will give you that either you want to change settings

just press no and your router will be on user mode which is


Hope this helps


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