I recently acquired the 21H1 iso image to regenerate my deployment images and ran into a snag when attempting to add a recovery partition to the image that allows the user to reinstall windows from installation media included in the image.
Basically, previous to 21H1, the iso images contained a 'install.wim' archive within the 'sources' subfolder of the installation media. I am using DISM to capture my installed and re-sealed via sysprep copy of Windows 10 with customizations. This generates a new install.wim image I can put onto the installation media.
21H1's installation media has changed from using install.wim, to using install.esd. I cannot find any information on generating an esd file, as they appear to be encrypted or something? I'm a bit confused about the matter. But the end result is, when I delete the install.esd file from the sources folder and replace it with a install.wim, the installation media simply doesn't work anymore.
To be clear, this is what I'm doing:
1. Install Windows 10 from original ISO
2. Boot the install, enter AUDIT mode.
3. Check for updates, install a few applications, make a few profile changes to the administrator account.
4. Use Sysprep to return the installation to 'uninstalled' OOBE mode so next boot will re-initiate hardware detect and OOBE.
5. Use DISM to capture the modified Windows to a new install.wim.
6. Copy new install.wim to the original ISO, removing install.esd
When I copy the new install.wim (removing install.esd from the install media as well) back to the installation media, the resulting new ISO doesn't work, setup complains a device driver must be missing cuz it can't find anything to work with.
All of these steps are being done in a virtual machine (VirtualBox)
Any tips or suggestions, or references to documentation on how to do this properly would be greatly appeciated. Thanks for reading!