Troubleshooting Tip: FortiAP forced to upgrade as soon as plugged into Fortigate.

• This behavior is expected when an image is uploaded onto the FortiGate for the FortiAPs and the image-download feature during join is enabled by default.
  
  config global
  

      config wireless-controller global

          set image-download enable

     end
  
  

• Verify there is an existing image uploaded on the FortiGate using below command: 

   

execute wireless-controller list-wtp-image

• To stop the force upgrade, remove all the images uploaded using the below command:

execute wireless-controller delete-wtp-image all

• Another method is to completely disable the image download from global settings:

config global

       config wireless-controller global

           set image-download disable

        end

• The feature can be disabled for a specific set of devices that are part of the same Operation Profile, or a single device that is the only member of the particular Operation Profile.
  
  config wireless-controller wtp
      edit <name>
          set image-download disable
      next
  end
  
  
• Another configuration that can trigger the upgrade is "firmware-provision-on-authorization" under vdom's wireless-controller settings, ensure this is disabled which is the default behavior.
  
   config vdom
     edit <vdom name>
        config wireless-controller settings
            set firmware-provision-on-authorization disable
        end