Why Custom HPE ESXi Image?
ESXi ISO, based on the standard VMware, is the easiest and most reliable way to install ESXi on HPE ProLiant servers. It includes all of the required drivers and management software to run ESXi on HPE ProLiant servers, and works seamlessly with Intelligent Provisioning.
Certain ProLiant servers require the use of the HPE Customized image for a successful installation. The drivers for the new network and storage controllers in the servers are integrated in the HPE Customized image and are not part of the generic ESXi image that is distributed by VMware. ESXi requires drivers for these controllers to be integrated as you are not able to insert them during installation. To determine if your server requires the HPE Customized image, refer to the Server Support Matrix.