Want to Replace IOS Version 17 with IOS Version 16

[Network_Wizard]

Greetings and salutations. I was given a project to take over, but one of the switches is in limbo right now. They want the default IOS, 17.03.04, to be replaced with an older IOS, 16.12.03a. Normally I would just copy the second IOS to flash and select which one to boot with. Unfortunately, the flash size is too small to hold both IOSes at the same time. I'm working with a Catalyst 9200-49 PoE+ The two IOSes are: cat9k_lite_iosxe.17.03.04.SPA.bin and cat9k_iosxe.16.12.03a.SPA.bin. My idea is to boot with IOS 16 from the tftp server, delete the files for IOS 17 to make room for IOS 16, and then install it. I tried numerous times to talk them out of downgrading and instead to just upgrade the switches already in the field to IOS 17, but they don't want to take down the whole network to do this. 

This seems long-winded and time-consuming. Is there a quicker way to do this? 

[Leo Laohoo]

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@Network_Wizard wrote:
Question. If I installed the lite version of 16.12.03a on the new switch, would it work with the switch on the other end of the link being the regular 16.12.03a image?

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9200 can only work on 9200 switches. 

A 9200 will not/never to boot a firmware meant for 9300/9400/9500/9600.  

[liviu.gheorghe]

@Network_Wizard is asking about a 9200 image: "The filename of the firmware for the 9200 should be cat9k_lite_iosxe.16.12.03.SPA.bin"

Let's see the show version outputs and we will know for sure.

[Network_Wizard]

@liviu.gheorghe @Leo Laohoo Thank you for your help with this. Apologies for the delayed response. I was on vacation for the last ten days. As much as I did not want to downgrade to an inferior IOS, this is what was wanted by the supervisor. 

[liviu.gheorghe]

Glad we could help and the downgrade was successful.