How to Upgrade Cisco IOS Bootstrap

Your Cisco IOS router runs the IOS which is the main operating system but it also has something called the “bootstrap”. This is the initial software that your Cisco IOS router boots, it’s kinda like the BIOS of your computer.

Just like IOS, the bootstrap can be upgraded on some router platforms. Sometimes on older hardware or when you upgrade from a very old to a new IOS version you might have to do this.

Switches also have a bootstrap. Since IOS 12.2(50) some switches will automatically upgrade the bootstrap when you upgrade the IOS image. I saw this first on a Cisco Catalyst 3750-X and it took about 20 minutes to upgrade…ouch!

In this tutorial I will show you how to do this on one of my 2811 routers. Let’s see what bootstrap version it has right now:

Router#show version 
Cisco IOS Software, 2800 Software (C2800NM-ADVENTERPRISEK9-M), Version 12.4(24)T8, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Sun 09-Sep-12 04:01 by prod_rel_team

ROM: System Bootstrap, Version 12.4(1r) [hqluong 1r], RELEASE SOFTWARE (fc1)

This 2811 router is running IOS image 12.4(24)T8 and bootstrap version 12.4(1r). The latest version of the bootstrap software can be found on the Cisco website.

I downloaded the latest bootstrap version from the Cisco website, let’s see how we can upgrade it:

Router#upgrade rom-monitor file ?
  archive:  SREC file to use
  cns:      SREC file to use
  flash:    SREC file to use
  ftp:      SREC file to use
  http:     SREC file to use
  https:    SREC file to use
  null:     SREC file to use
  nvram:    SREC file to use
  pram:     SREC file to use
  rcp:      SREC file to use
  scp:      SREC file to use
  system:   SREC file to use
  tar:      SREC file to use
  tftp:     SREC file to use
  tmpsys:   SREC file to use
  xmodem:   SREC file to use
  ymodem:   SREC file to use

I will use TFTP this time:

Router#upgrade rom-monitor file tftp://192.168.1.1/C2800NM_RM2.srec.124-13r.T11        
Loading C2800NM_RM2.srec.124-13r.T11 from 192.168.1.1 (via FastEthernet0/0): !!!!!!!
[OK - 1626367 bytes]

This command will result in a  'power-on reset' of the router! 
Continue? [yes/no]: yes

The file is about 1.6 MB so it doesn’t take long to copy. Once it’s done it will ask you to reboot the router…this is what you will see:

ROMMON image upgrade in progress.
Erasing boot flash eeeeeeeeeeeeeee
Programming boot flash ppppppppppp

Now Reloading

System Bootstrap, Version 12.4(1r) [hqluong 1r], RELEASE SOFTWARE (fc1)
Copyright (c) 2005 by cisco Systems, Inc.

Initializing memory for ECC
...

 Running new upgrade for first time


System Bootstrap, Version 12.4(13r)T11, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 2009 by cisco Systems, Inc.

You can see that the router rebooted and is now running the latest bootstrap code. You can also use the show version command again to check:

Router#show version 
Cisco IOS Software, 2800 Software (C2800NM-ADVENTERPRISEK9-M), Version 12.4(24)T8, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Sun 09-Sep-12 04:01 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T11, RELEASE SOFTWARE (fc1)

That’s the end of this tutorial, hopefully this was useful to you! If you have any questions feel free to leave a reply in our forum.

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Forum Replies

  1. why upgrade a bootstrap in the first place or what scenarios in which we need to upgrade the boostrap? Thanks Rene

  2. Hi Don,

    It’s not a common thing to do. It is possible that you need to do on an upgrade when you want to install a new IOS version. I also vaguely recall that the 1841 routers can boot from USB but only with a certain (newer) version of the bootstrap.

    Rene

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