You can install, upgrade, or migrate ESXi from a USB flash drive using a script that specifies the installation or upgrade options.

Supported boot options are listed in Boot Options.

Before running the scripted installation, upgrade, or migration, verify that the following prerequisites are met:

The system that you are installing, upgrading, or migrating to ESXi meets the hardware requirements for the installation or upgrade. See ESXi Hardware Requirements.

You have the ESXi installer ISO on a bootable USB flash drive. See Format a USB Flash Drive to Boot the ESXi Installation or Upgrade.

The default installation or upgrade script (ks.cfg) or a custom installation or upgrade script is accessible to the system. See About Installation and Upgrade Scripts.

You have selected a boot option to run the scripted installation, upgrade, or migration. See Enter Boot Options to Start an Installation or Upgrade Script.


Boot the ESXi installer from the USB flash drive.


When the ESXi installer window appears, press Shift+O to edit boot options.

ESXi Installer screen


Type a boot option that calls the default installation or upgrade script or an installation or upgrade script file that you created.

The boot option has the form ks=.


Press Enter.

The installation, upgrade, or migration runs, using the options that you specified.