There are several ways to achieve this, some that don’t even require modifying the WinPE boot.wim file since you don’t have to bake files into the WIM for them to be available in Rescue. Here are some ideas:
- If you use a USB flash drive for Rescue, the easiest way to have additional tools available is to just copy them onto the flash drive as regular files, then launch them by browsing to them in the File Explorer application that’s found in the taskbar of the Rescue environment. This is what I do.
- If you use disc-based Rescue Media, you can remove the disc after the Rescue environment loads and swap in another disc that contains the tools you want, then launch them as described above.
- If you want to get things into the WIM file, WIM files are mounted and modified using a Microsoft tool called DISM, which is built into Windows. If you’re running an older version of Windows and need to modify a WIM that contains a newer version, the recommended practice is to download the Windows ADK for at least the OS/PE version in the WIM or newer. If you’re running an equal or newer version of Windows, the DISM version you already have will be fine. Either way, this page shows how to mount a WIM, make changes, and commit changes: https://technet.microsoft.com/en-us/library/hh824814.aspx
- If you do the above starting with the generic Boot.wim file that’s downloaded from Microsoft as part of the ADK (rather than modifying the one generated by Reflect), you can then feed that file to Reflect as the baseline image from which it will build Rescue Media. Instead of using the default WIM, select “Custom WIM” in the Create Rescue Media wizard and select the file you’ve already customized. That way you won’t have to keep applying your customizations after the fact every time you rebuild your Rescue Media.