C9800-CL ap service pack installation issue

[Maurice Ball]

I upgraded my virtual Catalyst 9800 WLC to software version 17.09.04a without any issues. I rebooted the controller and all access points rejoined back to the controller. After the upgrade was completed I next tried to install the ap service pack filename:" C9800-CLcuniveralk9.17.09.04a.CSCwh93727.apsp.bin. When  installing the service pack I experienced an issue with some of the access points getting stuck in the status "initiated", some of the access points got stuck in the status "None" but the majority of the access points made it to status "complete". The issue I am seeing is because all the access points does not move to the complete status. I am unable to complete the installation of the service pack. Have anyone experienced this issue and know the solution for it?

[marce1000]

                    >... I am unable to complete the installation of the service pack.
 - How do you define unable ; if that related to those access points (initiated/none) ; try to reboot them and check if that can help
   Follow up on  overall AP behavior with : https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/217738-monitor-catalyst-9800-kpis-key-performa.html#anc4

 M.

[Rich R]

I presume that status you're referring to is the pre-download status of the AP?
As Marce says a reload of the AP can often resolve issues like that.
What model(s) of AP are having problems?
What version were you running before the upgrade to 17.9.4a?
Are the APs all local to the WLC?
Are the APs in flexconnect?
Are the APs at multiple different sites?
Did you configure a different site tag for each site?
If flex - have you configured Efficient Image Upgrade or direct download over CAPWAP?
The reason for all the questions: if you have APs in flex mode and use the same site tag at different locations the APs will try to download the image from what they think are neighbours in the same site tag even though the "neighbour" AP might be at a different location - which causes the download to fail.

[Maurice Ball]

I presume that status you're referring to is the pre-download status of the AP? Correct but I also restart the WLC and saw the same issue.
As Marce says a reload of the AP can often resolve issues like that.  I restarted the access points. I also tried clearing all the configuration on one of the access points and I still got the same issue.
What model(s) of AP are having problems? Sorry this is at a customer site and I don't remember all of them at the moment but I know one is a Air-Cap1702I-E-K9 and another one is a Air-Cap 2702I-E-K9.
What version were you running before the upgrade to 17.9.4a? 17.3.5a
Are the APs all local to the WLC? some are local 
Are the APs in flexconnect? some are flexconnect
Are the APs at multiple different sites? yes
Did you configure a different site tag for each site? I am seeing it on two different site tags.
If flex - have you configured Efficient Image Upgrade or direct download over CAPWAP? direct download over CAPWAP
The reason for all the questions: if you have APs in flex mode and use the same site tag at different locations the APs will try to download the image from what they think are neighbours in the same site tag even though the "neighbour" AP might be at a different location - which causes the download to fail.

[Rich R · Accepted solution]

> If flex - have you configured Efficient Image Upgrade or direct download over CAPWAP? direct download over CAPWAP
So your flex profiles (which should also be unique per site) have "no predownload" configured?

Another post today reminded me that the IOS APs (like 1702/2702) had a bad habit of flash getting corrupted so might be worth checking.
https://www.cisco.com/c/en/us/support/docs/field-notices/703/fn70330.html
https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/213317-understanding-various-ap-ios-flash-corru.html
https://wifision.nl/2018/06/05/understanding-various-ap-ios-flash-corruption-issues/