When creating OVF or OVA files in current versions of vCenter Server, the NVRAM file is not exported with the OVF. This issue occurs because the EFI-based Linux virtual machines requires the NVRAM file to boot successfully.
Note: This will not impact any virtual machines which are Cloned, relocated via Storage vMotion, and is specific only to OVF/OVA exported EFI based Linux Virtual Machines. BIOS based virtual machines are not affected.