🧰 FixWindowsISO_with_Oscdimg_v3.1.ps1

Overview

FixWindowsISO_with_Oscdimg_v3.1.ps1 automates the process of rebuilding a Windows installation ISO to bypass TPM and Secure Boot checks, while ensuring that oscdimg.exe is automatically installed, copied into the system, and safely cleaned up afterward.

It performs the following tasks:

  1. Ensures administrative privileges.
  2. Locates or installs Microsoft’s OSCDIMG utility (from the ADK Deployment Tools).
  3. Automatically copies oscdimg.exe into C:\Windows\System32.
  4. Uninstalls the ADK immediately after extracting (Option A cleanup).
  5. Prompts for or accepts an existing Windows ISO.
  6. Mounts and copies ISO contents to a working directory.
  7. Removes the TPM enforcement component (sources\appraiserres.dll).
  8. Rebuilds the ISO with proper boot sectors for BIOS/UEFI.
  9. Cleans up all temporary files and logs build attempts.

⚙️ Key Features

Feature Description
Automatic Elevation Script re-launches itself with Administrator privileges if needed.
Winget-Based ADK Install Uses Winget to install Microsoft.WindowsADK and optionally Microsoft.WindowsADK.PEAddon.
Automatic Cleanup Removes ADK tools right after copying oscdimg.exe.
TPM Bypass Deletes appraiserres.dll from the ISO source tree.
Smart Boot Strategy Automatically selects BIOS/UEFI boot images found in the ISO (etfsboot.com, efisys.bin, etc.).
Robust Logging Each oscdimg build attempt logs stdout/stderr to %TEMP%\Oscdimg-Logs-<GUID>.
Failsafe Cleanup Always removes temporary work directories, even after errors.

🪟 Requirements

  • Windows 10/11 (x64 recommended)
  • PowerShell 5.1 or higher
  • Administrator rights
  • Optional: Internet access for Winget-based ADK install

🧩 Script Flow Summary

1. Assert-Admin

Ensures the script is running elevated. If not, it relaunches itself as Administrator.

2. Ensure-Oscdimg

  • Searches for oscdimg.exe in PATH, System32, and known ADK locations.
  • If not found:
    • Installs the Windows ADK via winget install -e --id Microsoft.WindowsADK.
    • Copies oscdimg.exe to System32.
    • Immediately uninstalls the ADK via winget uninstall.
  • Fallback: instructs the user to install ADK manually.

3. Select-IsoIfNeeded

Prompts the user with a file dialog to select a .iso if not provided as a parameter.

4. Expand-Iso

Mounts the ISO, copies its contents via robocopy, and dismounts it.

5. Remove-AppraiserRes

Deletes sources\appraiserres.dll (the TPM enforcement file).

6. Build-Iso

Rebuilds the ISO using oscdimg.exe with multiple strategies and logs all attempts.

7. Cleanup

Removes temporary directories and retains logs for review.

🧾 Usage

Set-ExecutionPolicy Bypass -Scope Process -Force
.\FixWindowsISO_with_Oscdimg_v3.1.ps1

With parameters:

.\FixWindowsISO_with_Oscdimg_v3.1.ps1 -IsoPath "C:\ISOs\Win11_25H2_English_x64.iso" -OutputIsoPath "C:\ISOs\Win11_NoTPM.iso"

📁 Outputs

Path Description
%TEMP%\WinISO-Fix-<GUID> Temporary expanded ISO contents.
%TEMP%\Oscdimg-Logs-<GUID> All oscdimg logs.
<OriginalDir>\Win11_XXXX_NoTPM.iso The rebuilt ISO.

⚠️ Common Issues

Error Cause Solution
Access is denied ISO output file in use Close any ISO viewers or Explorer windows.
Could not open boot sector file etfsboot.com Missing BIOS boot file Build will fall back to UEFI-only.
oscdimg.exe not available ADK install failed Run manually: winget install -e --id Microsoft.WindowsADK.
Mount-DiskImage fails ISO already mounted Dismount manually, then retry.

🧠 Design Notes

  • Winget-first install ensures correct platform version.
  • No bootstrapper downloads — avoids platform mismatch errors.
  • Silent uninstall keeps the system clean.
  • Works on PowerShell 5.1 and 7.x.

🧩 Licensing

Includes oscdimg.exe (© Microsoft) from the Windows ADK, used under its redistribution terms.

🪙 Author

Script + Documentation: Adapted with ChatGPT GPT‑5 for Preston S. Powell, October 2025.