.NVRAM File Format

Introduction

The .nvram file holds the non-volatile memory of a VMware virtual machine's firmware. VMware's article on the contents of a Fusion bundle says it "stores the state of the virtual machine's BIOS", and the vSphere Virtual Disk Development Kit guide says it stores the BIOS or UEFI customisations of a machine, usually only the boot drive setting and the boot order that matter. The .vmx names it in its nvram key (nvram = "Test.nvram"), which libvirt reads as the loader's NVRAM file.

Structure

VMware has not published the layout of the file, and no open-source description was found in the sources read for this page. This page therefore lists no fields. The viewer shows the file as bytes. (For comparison, Parallels' firmware store NVRAM.dat has been observed to be a UEFI firmware volume; nothing says the same of VMware's file.)

Not described

Unknown

• Reference: the whole layout of the file: its signature, any header, how BIOS settings or UEFI variables are stored, and checksums. It would have to be worked out from real files.
• Viewer: there is no viewer: the file shows as bytes with this page as its reference.

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