The RBSU Erase option allows you to erase the system configuration and boot drive. On versions of RBSU without this new feature, the Erase Non-Volatile Memory option is available in the Advanced Options menu of RBSU, allowing you to erase the system configuration by resetting the NVRAM to an initial, factory state.
The new option, Erase NVRAM/Boot Disk, also erases the system configuration by resetting the NVRAM, but erases the boot disk as well. The RBSU Erase option should only be used when you are redeploying a server and are required to erase the NVRAM and boot drive to reinstall the operating system. If available for the server, the Erase NVRAM/Boot Disk option is listed under the Advanced Options menu in RBSU.