Solved: Cisco 2821 Config-Register Issues

JakeMIGSMN · ‎10-30-2010

Hey guys,

So I just fired up a used 2821 for the first time and broke into it and by accident, instead of typing in "confreg 0x2142", I fat fingered it and typed in "confreg 0x21421" and reset the router. Now I fire it up and it's just all garbled with random texts and symbols. This has happened to me before and I've been able to set Hyper Terminal to a different baud rate and it has worked but this time I've tried all the different baud rates and no luck. Any ideas? Thanks.

Peter Paluch · ‎10-31-2010

Hi Jacob,

Don't worry, this cannot be as bad as it looks. I do not believe you could damage anything.

Make sure you are connected to the CON port and not the AUX. Try to power-cycle the router and send the Break sequence multiple times to force the router to jump to ROMMON (ideally, have the COM port set to a low speed like 1200 or 2400 bps). Then try modifying the port speeds again, starting from 1200 bps and ending on 115200 bps. 8 databits, no parity, 1 stop bit, no flow control. Everytime you change the speed, hit Enter numerous times to see whether the normal ROMMON prompt appears.

Best regards,

Peter

View solution in original post

Peter Paluch · ‎10-31-2010

Hi Jacob,

Don't worry, this cannot be as bad as it looks. I do not believe you could damage anything.

Make sure you are connected to the CON port and not the AUX. Try to power-cycle the router and send the Break sequence multiple times to force the router to jump to ROMMON (ideally, have the COM port set to a low speed like 1200 or 2400 bps). Then try modifying the port speeds again, starting from 1200 bps and ending on 115200 bps. 8 databits, no parity, 1 stop bit, no flow control. Everytime you change the speed, hit Enter numerous times to see whether the normal ROMMON prompt appears.

Best regards,

Peter

JakeMIGSMN · ‎10-31-2010

i have already tried that but ill give it another shot, thank you for the reply.

Peter Paluch · ‎10-31-2010

Hi Jacob,

Yes, I know you've tried it but I would really like you to give it yet another shot.

Best regards,

Peter

JakeMIGSMN · ‎10-31-2010

i wont be in the office until tomorrow but i will keep you posted, thanks for the help

Peter Paluch · ‎10-31-2010

Jacob,

Okay. I may try to reproduce your problem on one of our 2811 routers in the lab on Tuesday - but I shall keep the router configured with an IP address so that I have some way of accessing the router after all.

Best regards,

Peter

JakeMIGSMN · ‎10-31-2010

thanks a lot, I appreciate it

JakeMIGSMN · ‎11-01-2010

I got it fixed. You were right Peter, just go back and mess around with the different baud rates. It ended up being baud rate 57600, 8 data bits, parity set to none, stop bits set to 1 and flow control set to none. Thanks again for the tip, I guess going back and double checking your work really does help!

Peter Paluch · ‎11-01-2010

Hello Jacob,

I am really glad you got it working. Being a NetAcad instructor, I see lots of configuration register values messed

Best regards,

Peter