Booting in rommon mode

[marcelo.sequeira]

hi

I have a Catalyst 4506e that works fine but if reload, it boots in rommon mode.

I can start it with a boot command, but by default, i must type a command. My config-register is 0x2102.

Thanks

[Arumugam Muthaiah · Accepted solution]

Hi,

The switch could wind up in ROMmon mode due to these reasons,

• A switch reload or crash after the image was corrupted or deleted
  
• The Compact Flash which holds the system image has been removed
  
• The configuration register has been changed incorrectly. The configuration register value of 0x0 always brings the switch to ROMmon mode. The typical configuration register is 0x2102, with the boot system flash command pointing to the system image to load
  
• The boot variable is incorrect, but a valid image is still present
  

In our case, config register is set correctly as 0x2102, I would suggest you to verify the boot variable.

1. When the switch gone into rommon, Issue the dir bootflash: command to list the files present in the bootflash, or issue the dir slot0: command to list the files present in the Compact Flash device.

          rommon 1 >dir bootflash:
          rommon 2 >dir slot0:

Note: The reason the switch reboots continuously is because the system image file name specified does not exist, but there is a valid file in the bootflash and slot0:. Also, the system image file name specified is case sensitive. If it is not specified correctly, it causes a continuous reboot.

2. The system is back up, Issue the dir bootflash: command to note the file in the bootflash:. Issue the dir slot0: command if you loaded the system file present in the slot0:.

Issue the show bootvar command to check the current boot variable.

example:
Switch#show bootvar
BOOT variable = bootflash:cat4000-is-mz.121-8a.Ew,1
CONFIG_FILE variable does not exist
BOOTLDR variable does not exist

3. Remove the existing incorrect boot variable and add the correct one. Issue the configure terminal command in order to do this.

Switch#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#no boot system flash bootflash:cat4000-is-mz.121-8a.Ew
Switch(config)#boot system flash bootflash:cat4000-is-mz.121-11b.EW
Switch(config)#end

4. Save the configuration from running to startup, by issuing the write memory command.

Switch#write memory
Building configuration...
Compressed configuration from 4359 bytes to 1730 bytes[OK]

5. Check the boot variable again to make sure it is set properly so that the switch boots up the correct system file on the next reboot

Refer:

http://www.cisco.com/en/US/products/hw/switches/ps663/products_configuration_example09186a0080094ecf.shtml#image

Regards,

Aru

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[marcelo.sequeira]

Hi Arumugam

First, thanks a lot for your help.

I understand that if my image is corrupted or deleted, it will be impossible to start with a "boot" command from the rommon mode.

I have no device available on slot0 and my config-register is 0x2102, so my problem must be an incorrect boot variable.

The result of show botvar is

Switch#show bootvar

BOOT variable = variable does not exist

CONFIG_FILE variable does not exist

BOOTLDR variable does not exist

configure-register is 0x2102

I think that i will must set my boot variable. If yes, how must i do it?

Thanks again

Marcelo

[Leo Laohoo]

From the ROMmon, can you issue the command "dir flash:"?

[marcelo.sequeira]

It' the result the same that "sh bootflash:" from exec mode? If yes, i have the the file that i need.

[Arumugam Muthaiah]

Hi Marcelo,

Yes, this will show the result and helps you to find the image where it is located.

rommon 1 >dir bootflash:

   File size                  Checksum      File name

   --------------------------------------------------

   6516904 bytes (0x6370a8)   0x7b7edb21    cat4000-is-mz.121-11b.EW

   Total space = 61341696 bytes, Available = 54824664 bytes

or

rommon 2 >dir slot0:

   File size                  Checksum      File name

   --------------------------------------------------

   6516904 bytes (0x6370a8)   0x7b7edb21    cat4000-is-mz.121-11b.EW

   Total space = 128057344 bytes, Available = 121540312 bytes

• Once you find the image (if it is stored on bootflash), please run the below command to boot,
  

rommon 2 >boot bootflash:cat4000-is-mz.121-11b.EW

or

rommon 2 >boot slot0:cat4000-is-mz.121-11b.EW

Once the system restored, please set the boot variable as suggested previously.

Regards,

Aru

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