Generating FFU images

1. Install your ISO, WIM or ESD image on a disk drive using WoR

If you have a really slow SD card or USB drive, we recommend creating a 15 GB VHDX using Disk Management and applying the image to it instead. The storage in your PC will most likely be faster.

2. Open a command prompt window as administrator

In the opened window, type the following command and read the info below before hitting enter:

DISM.exe /capture-ffu /imagefile=X:\WindowsOnRaspberry.ffu /capturedrive=\\.\PhysicalDriveY /name:WoR-FFU

X:\WindowsOnRaspberry.ffu is the destination path of the FFU image. Change it to your own location.

PhysicalDriveY is the drive that you wish to generate the FFU image from. Change Y with the disk number of the drive.

WoR-FFU is the signature required by WoR, followed by some additional parameters, delimited by colons (:) :

• the MBR, GPT (RPi 3-only) and GPT-Native (RPi4-only) parameters specify the partition scheme used for the installed image (step 1). Only one must be specified!

  Since version 2.1.0 of the imager, FFUs made for Raspberry Pi 4 must specify GPT-Native if GPT was used for the installation, and those made for older models must specify GPT. The latter images are not compatible with Raspberry Pi 4.

• the Compact parameter specifies that the image can fit on an 8 GB device (Compression was used). This is required if you want to apply the FFU image to a drive that has less than 14 GB of available space.
• the ARM64 and ARM32 parameters indicate the architecture of the installed image. This can be omitted if an ARM64 image was used.

Example:

DISM.exe /capture-ffu /imagefile=D:\Build19041Compact.ffu /capturedrive=\\.\PhysicalDrive2 /name:WoR-FFU:GPT:Compact

The command above tells the tool to create a FFU image at D:\Build19041Compact.ffu from disk 2, and that the GPT partition scheme and LZX compression have been used when the ARM64 WIM image was installed.