When you have a matching Windows OS in the deployment share, MDT uses the BOOT.WIM from that source. When they don’t match, MDT uses WINPE.WIM from the ADK that is installed.
While this is generally preferable, you may want force it back to using the Microsoft ADK for WinPE booting.
You will need to manually edit the Settings.xml file to make this change. I have also included the powershell commands that will do this for you at the bottom.
Manual Steps to Make the Change:
1) Start notepad as an administrator.
2) Open file <DeployRoot>\Control\Settings.xml (e.g. C:\DeploymentShare by default)
3) Locate <Boot.x86.UseBootWim> and <Boot.x64.UseBootWim> and change the True setting to False.
It will look like this when changed:
PowerShell Commands to Make the Changes:
Make sure to change the $FolderPath variable to point at your deployment share root folder.
$FolderPath = C:\DeploymentShare
$XMLFile = "$FolderPath\Control\Settings.xml"
[xml]$SettingsXML = Get-Content $XMLFile
$SettingsXML.Settings."Boot.x86.UseBootWim" = "False"
$SettingsXML.Settings."Boot.x64.UseBootWim" = "False"