Why not add your USB hard drive as a datastore in ESXi? In this How-To I’ll guide you through it
VMWare ESXi
Different guides and ho-to’s for VMWare ESXi aka VMWare vSphere Hypervisor
Backup TPM recovery key from ESXi host
It’s important to make sure that you have a backup of the TPM recovery key from your ESXi hosts, in this guide I’ll show you have to do that
Update VMWare ESXi on single host (WebGUI)
How to update VMWare ESXi on single host with the WebUI