Reading Time: 1 minute In previous post we have already see how add custom drivers to an ESXi installation ISO and how use ImageBuilder to make custom ESXi ISO, but in other cases you may need to define some custom settings during the installation or add custom vib files. Booting from CD is not the only way, but custom ISO could be used also for boot from USB or for boot from virtual devices (like the iDRAC or ILOE).