You can use cluster images to perform firmware updates on the ESXi hosts in a cluster. Using cluster images simplifies the host update operation. With a single operation, you update both the software and the firmware on the host.
To apply firmware updates to hosts in a cluster, you must deploy and configure a vendor provided software module called hardware support manager. The deployment method and the management of a hardware support manager is determined by the respective OEM. For example, the hardware support manager that Dell EMC provides is part of their host management solution, OpenManage Integration for VMware vCenter (OMIVV), which you deploy as an appliance.
You must deploy the hardware support manager appliance on a host with sufficient disk space. After you deploy the appliance, you must power on the appliance virtual machine, log in to the appliance as an administrator, and register the appliance as a vCenter Server extension. Each hardware support manager has its own mechanism of managing firmware packages and making firmware add-ons available for you to choose.
For detailed information about deploying, configuring, and managing hardware support managers, refer to the vendor-provided documentation.