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FFS, which stands for: 'For F@%k's Sake, IT'S CALLED A MODULE!!' is a convenient repackaging of the EDK2's GenSec and GenFfs utilities, with the aim of easing up the generation of what intel/EDK calls FFS's (whatever that abbreviation means) which are MODULES, that can be integrated into a regular UEFI firmware.

This can be useful if, for instance, you have UEFI driver executables, which you want to make available in your UEFI "BIOS".


BSD 2-Clause, as per the EDK2.


The sources included in this project are all unmodified versions of the same files from the BaseTools/Source/C/ repository of the EDK2.

The only elements added are the Visual Studio 2015 project files (much more convenient than whatever the EDK2 wants you to set up for recompilation) and some useful scripts.



  • Open the solution file in Visual Studio and select 'Build Solution'

A brief breakdown of UEFI firmware MODULES

An UEFI firmware driver module (FFS) should be composed of the following:

  • An FFS header
  • A PE32 section containing the driver EFI executable
  • A Driver Name ("User Interface") section
  • A driver Version section

In practice, this could appear as follows:

Address Size  Designation
------- ----  -----------

0x0000  16    Name (EFI_GUID)
0x0010  1     IntegrityCheck.Header (Header Checksum)
0x0011  1     IntegrityCheck.File -> set to 0xAA (FFS_FIXED_CHECKSUM) and clear bit 0x40 of Attributes
0x0012  1     FileType -> 0x07 = EFI_FV_FILETYPE_DRIVER
0x0013  1     Attributes -> 0x00
0x0014  3     Size, including header and all other sections
0x0017  1     State (unused) -> 0X00

0x0000  3     Size, including this header
0x0003  1     Type -> 0x10 (EFI_SECTION_PE32)
0x0004  ####  <PE data>

0x0000  3     Size, including this header
0x0003  1     Type -> 0x15 (EFI_SECTION_USER_INTERFACE)
0x0004  ####  NUL terminated UTF-16 string (eg "FAT\0")

0x0000  3     Size, including this header
0x0003  1     Type -> 0x14 (EFI_SECTION_VERSION)
0x0004  ####  NUL terminated UTF-16 string (eg "1.0\0")

Creating a driver UEFI firmware MODULE

From what was exposed above, and starting with an ntfs_x64.efi driver executable, the generation of the relevant UEFI driver firmware MODULE can be accomplished as follows (NB: you'll need to replace the 1234... GUID with your own):

GenSec -o pe32.sec ntfs_x64.efi -S EFI_SECTION_PE32
GenSec -o ver.sec -S EFI_SECTION_VERSION -n "1.0"

GenFfs -d 1 -g "12341234-1234-1234-1234-123412341234" -o ntfs.ffs -i pe32.sec -i name.sec -i ver.sec -t EFI_FV_FILETYPE_DRIVER

Or you can also use the GenMod batch file under Scripts, which takes the driver executable and an optional GUID as parameters.

For a detailed guide on how you may use FFS to insert an NTFS EFI driver into a VMWare firmware image, please have a look here.

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