FYI : https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/214855-ios-xe-wireless-feature-list-per-release.html#toc-hId-18123547
M.
- Checkout this procedure instead : https://www.cisco.com/c/en/us/td/docs/routers/access/4400/troubleshooting/guide/isr4400trbl/isr4400trbl02.html (it is different from what you are currently doing)
M.