Stuck trying to reset password - only text that shows on reboot is "Checking for PCIe device...done" and then one character is repeated forever.

[ghostie]

I'm in a classroom setting and having a bad time. A student accidentally mis-typed when entering in a password. It says "bad secret" or "bad password" when trying to enter the 'enable' command. I was following the steps from this post to attempt to recover or reset the password: 

https://community.cisco.com/t5/network-management/bypass-or-reset-console-password/td-p/3316309

Everything was fine until Step 4 - reset. When the router started to reboot, the only text I have seen it display is "Checking for PCIe device...done" and then the router keeps displaying this text over and over again ▒▒▒▒▒▒▒▒▒. A reset or poweroff/on cycle has not changed anything. It keeps doing this. Ctrl+break or Ctrl+shift+x+6 is doing nothing. I cannot type any text into the console. I have tried changing speeds and PuTTY settings with no success. My supervisor seems stumped and has not seen this before either. The same thing keeps happening. I have been searching for a solution to this and haven't seen anyone with the same problem as me. Any help is appreciated.

Some background for you: I am working off of a Cisco 4221 router. It is connected to a PC via console port and I am using PuTTY for my emulation software. No SSH or Telnet settings were configured before the password was mistyped by this student. 

[Giuseppe Larosa]

Hello ghostie,

have you logged all of your console activity on Putty ?

Try to verify if you have by mistake changed the console port settings by changing the config register value.

Edit:

the document procedure is misleading it says the config register to ignore the startup confguration  has to set a specific bit, but you don't need to set it to 0x00040.It only means the second rightmost less significant hex digit has to be 4.

See these steps from final post in the thread the config-reg should be set from 0x2102 to 0x2142.

NOTE = original(normal) confreg = 0x2102

Change confreg:
1 - on boot = cntr + c

Note original confreg:

2 - rommon 1>confreg

Note - say no to change config settings in above

Change confreg:
3 - rommon 2> confreg 0x2142

4 - rommon 3> reset

Router boots but bypasses config:

5 - router>en
6 - router#copy start run

Here is where you change the username and password:
7 - Router_name(config)#username cisco password cisco

Put the config-reg back to what it was:
8 - Router_name(config)#config-register 0x2102
9 - Router_name(config)#end
10 - Router_name#wr
11 - Router_name#reload

when router is back to normal startup - make sure config register is back to normal 0x2102

12 - Router_name#show ver

Edit2:

see the following to decode config register settings

https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/50421-config-register-use.html#anc6

Hope to help

Giuseppe

[ghostie]

Hi Giuseppe, thanks for your response. Unfortunately logging was not enabled when I entered my steps. Important lesson learned I guess. :( However, I am quite confident that I entered the steps in order and entered 0x2142 for the new confreg value. Unfortunately this may have to be something we have to ask Cisco for help with directly through a ticket. I was mostly curious if anyone else had this same issue as me. I was searched a lot about it and wasn't able to find someone with the exact problem. Thank you for your response though!