OSDeploy Boot: Customize WinPE with a PowerShell Script

Add a custom PowerShell script that runs while Build-OSDeployBoot services the mounted WinPE image.

Place a PowerShell script in the shared boot-winpescript library when it must customize the mounted WinPE image during Build-OSDeployBoot.

A WinPE build script runs on the OSDeploy workstation in the current PowerShell session. It does not become a startup script unless the script explicitly copies content into the mounted image.

Create the Script

Create the shared script directory and a script that writes a marker file into WinPE:

$ScriptDirectory = Join-Path $env:ProgramData 'OSDeployCore\boot-assets\boot-winpescript'
$ScriptPath = Join-Path $ScriptDirectory 'Add-ContosoMarker.ps1'

New-Item -Path $ScriptDirectory -ItemType Directory -Force | Out-Null

@'
$MountPath = $global:BuildMedia.MountPath

if (-not $MountPath -or -not (Test-Path -LiteralPath $MountPath -PathType Container)) {
    throw "The OSDeploy WinPE mount path is not available."
}

$Destination = Join-Path $MountPath 'Windows\System32\Contoso'
New-Item -Path $Destination -ItemType Directory -Force | Out-Null
Set-Content -LiteralPath (Join-Path $Destination 'Build.txt') `
    -Value "Built $([datetime]::Now.ToString('s'))" `
    -Encoding utf8
'@ | Set-Content -LiteralPath $ScriptPath -Encoding utf8

Use $global:BuildMedia.MountPath for files that belong inside WinPE. Throw when required input or an operation fails so the build log identifies the problem.

Select the Script

Start an interactive build and select Add-ContosoMarker.ps1 when the WinPE script picker appears:

Build-OSDeployBoot

Build and Verify

Complete the remaining prompts to build the media. The script runs near the end of mounted-image servicing, before WinPEStartup content and drivers are added. Script success-stream output is passed through by the build step; a script failure writes a non-terminating error and later build steps can continue.

Boot the resulting media and confirm this file exists:

X:\Windows\System32\Contoso\Build.txt

Use boot-mediascript instead when a script must modify the completed media after the WIM is dismounted. See OSDeployCore Boot-Assets for the two script lifecycles.