Upgrade from 3.16.04b.s to 17.9.4a Cisco 4331 router

[SallySmith61817]

How would one upgrade from 3.16.04b.s. to 17.9.4a a 4331 router?  The current rommon is 16.12. Can I go direct or do I  have to install other OS's before I move from 3 to 17?

[M02@rt37 · Accepted solution]

Hello @SallySmith61817 

Follow these steps :

https://www.labminutes.com/blog/2016/04/cisco-isr-4000-upgrade-guide-3x-denali-162

ROMmon

[SallySmith61817]

Thank you so much!  I'm going to try this weekend and let you know how it goes!

[SallySmith61817]

What I ended up doing is upgrading the device from 3.16 to 16.8.1 to 17.9.4a and that worked.  Thanks for the info!

[Leo Laohoo]

Cisco ISR & ASR 1k Routers: IOS-XE/Firmware Upgrade (Install Mode)