How to get to rommon prompt

Unanswered Question
Sep 5th, 2007
User Badges:


I've got a 3560 switch which I'd like to get to the rommon prompt. My question is how do I do that from the enable prompt. Currently its running through console and I'm accessing it via minicom on linux. Additionally I don't have physical access to it. Any chance of doing this remotely.



  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
jorgenolla Wed, 09/05/2007 - 11:06
User Badges:

rommon prompt will only be available through your console port. If that switch was connected to an access server, you might have a chance to do this remotely.

Best Regards

dan_track Wed, 09/05/2007 - 11:09
User Badges:


I tried that but there isn't a "confreg" command available to me. Any reason why?



dan_track Thu, 09/06/2007 - 00:06
User Badges:


Just wondering if anyone can supply any more input on this. Basically I just want to upgrade the IOS and the only way I know how is by xmodem or zmodem (no network connectivity for tftp), but these require you to be at the rommon prompt.

Any ideas?


nambi_gct Thu, 09/06/2007 - 07:44
User Badges:
  • Bronze, 100 points or more

Hi Dan,

I assume that you are using console port to connect to the switch.If so,

1) You can set the config register value to 0x0 (with the command "config-register 0x0")and reload the box.

2) Or you can reload the box and can give "send brk" when it boots up.

That will put the box in rommon.

rays Wed, 11/21/2007 - 05:12
User Badges:

Hi there. any one know how to break into rommon when you are not directly connected to the console? I.e. telnet from pc to switch. reverse telnet to a terminal server and then console from terminal server to switch?

I have tried a few terminal emulators and i just cannot get the switch to accept the break sequence when i reload?

Any ideas?



bvsnarayana03 Wed, 11/21/2007 - 05:37
User Badges:
  • Silver, 250 points or more

If u can access the switch by telnet, then u need to change the config-register value to 0x2142. The command is, "config-register 0x2142". Then a reboot will take the device to rommon. But there after u'll have to work through console.

Though it is recommended u've someone at remote site to help u in adverse consequences.

glen.grant Wed, 11/21/2007 - 05:34
User Badges:
  • Purple, 4500 points or more

You just want to upgrade thru telnet ? Just put your image on a device that is running a tftp server and log into the 3560 and do a copy tftp flash: command which load the image to flash . Change your boot statement and reload the switch . The tftp server can even be your pc just download a tftp program and program it , turn off your FW on your pc temporarily or allow it thru your pc firewall and download to the 3560. This is the way most people do it or they have a dedicated tftp server on the network . Xmodem is reserved for recovering from corrupted images and such because it is so slow . You don't have anywhere on the network you can telnet too ??


This Discussion