I am driving myself a little bit mad on this one. I am planning an IOS 16.12.04 upgrade (from 16.12.02) on two stacked Catalyst 9200 switches. These switches are located in Germany (I am located in England) so I need to make sure nothing goes wrong. The upgrade deadline is approaching and I am not sure if I am am planning this correctly. I found the document below which looked good but I realised this doesn't mention a stack anywhere apart form the boot flash stage "If your switches are configured with auto boot, then the stack will automatically boot up with the new image. If not, you can manually boot flash:packages.conf".


My senior colleague said that I need to make sure I upload and set the secondary switch to use the new version as well but as far as I can see this is not mentioned in the above document. Can I use the above document instructions and only install the new IOS on the master switch after which it replicates the new image to the slave switch when that is rebooted?

Also, I need to cleanup the unused installation files so in the case of a rollback needing to be performed what is the best way as I won't have the old .bin file. Do I have to transfer the old .bin file and install the old firmware again? Many thanks in advance!

Kind Regards, Michael Borg

  • 2
    Your colleague is incorrect. If the switches were independent, yes, they'd need to be upgraded separately but, because they're in a stack, they act as one single switch part of the process deploys the image to all stack members and upgrades them all. You CAN have it only upgrade individual members, but I digress.
    – Jesse P.
    Apr 5, 2021 at 21:14
  • Yes, you can use that guide you found. As far as rollback goes, if you think that's a possibility, why are you planning to remove the old (current) images immediately and not like a week or more down the road?
    – Jesse P.
    Apr 5, 2021 at 21:22
  • 1
    Hi Jesse P, Apologies for my very late reply and thanks for your input. I need to remove the 16.12.02 .bin file to free up space on the switch for the new 16.12.05b (I decided against 16.12.04 and went with 16.12.05b instead). I have a bout 50mb less space than what Cisco recommends and I don't want to take any risks running out of space. I do oooed through the flash files for something I can delete but didn't find anything substantial. Kind Regards, Michael Borg
    – Mike.Borg
    Apr 11, 2021 at 17:46
  • Did any answer help you? if so, you should accept the answer so that the question does not keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
    – Ron Maupin
    Dec 23, 2021 at 17:35

1 Answer 1


To answer your questions: The master will install on itself, then transfer and install on slave and then reboot the switches. You should be able to follow the process until reboot.

1.) based on the release note it should auto boot everything : you can check with "show boot system" Just double check your boot variable is set correctly. packages.conf

Manual boot = no

2.) If you have the space you can leave the files BUT if you're in INSTALL mode you will have to re-install old IOS

Read this link, or the latest release notes for your IOS verion:


I'm assuming your running the image in "INSTALL" mode, you can check using the show version command

Only upload the file to the master, the behavior of stack upgrades has changed since 3750s (bundle mode) and on install mode. which sounds like what your colleague is referring too. You can upload the image to the standby switches but the install process will transfer it again.

After you upload the files (must be done after the clean command, otherwise it will be deleted ).

if you're unsure build an mini POC to test it.

Closing notes make sure:

  1. Check your crypto key is updated before starting and back up everything
  2. Boot image is setup before hand, packages.conf (follow the upgrade notes)
  3. SSH service takes a little longer after upgrade could take up to ~+5mins after ping.

and as always you should make sure you can get access to console as a back up. Always better to have some smart hands available than impacted downtime. I'm sure they have desktop support or something onsite. All they need is a mini usb cable.

  • Hi onxx, Apologise for the late reply and thanks for your input. Yes, the switch such is in install mode. I'll check the crypto key tomorrow and we have hands on about 30 minutes away on the day so if disaster strikes I'll call him who will have a console cable. Thanks for your answer.
    – Mike.Borg
    Apr 11, 2021 at 17:51
  • @Mike.Borg good luck, its pretty straightforward now with install mode.
    – onxx
    Apr 13, 2021 at 0:32
  • Hi onxx. Thanks! Yeah it should be very straight forward. I just wanted to cover all basis in the case of something going wrong. This is a major peace of equipment, it's in another country and I'm still in my probation period so I want to do everything I can to prepare. Thanks again for your input!
    – Mike.Borg
    Apr 14, 2021 at 6:25

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