Regarding this link:

https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/8.0/html/updating_red_hat_jboss_enterprise_application_platform/updating-jboss-eap-using-the-jboss-eap-installation-manager_default

First, it wasn't clear to me why the instructions say to download the jboss-eap-installation-manager when one is already included with the base EAP installation. It would be good to clarify why a person would need another one.

Which leads me to the next point....

I tried to use the one that was already in my base EAP installation but it failed on the final step:

Applying updates


ERROR: java.nio.file.FileSystemException: c:\jboss-eap-8.0\jboss-modules.jar: The process cannot access the file because it is being used by another process

Which basically means on Windows, you can't run the installer in the base image you want to update. You really do need a separate installer to avoid the Windows file locking mechanism.