How to test preproduction drivers with Secure Boot enabled

Article
07/10/2024

On retail and production systems, the Windows kernel only trusts and loads drivers with a production WHQL/WHCP signature. To test preproduction drivers, it's required that driver developers enable TESTSIGNING to enable nonproduction drivers to load. TESTSIGNING requires disabling Secure Boot, to present a difference in the testing and production environments.

The Windows kernel supports loading preproduction drivers signed with the WHQL/WHCP preproduction signature. The WHQL/WHCP signature is accessible through the Microsoft Hardware Developer Center (HDC).

Prerequisites

Sign your preproduction drivers with Partner Center Hardware dashboard
Download EnableUefiSbTest.exe from the latest version of the Windows Driver Kit (WDK) or from Download Center. The default setup location of the EnableUefiSbTest tool is C:\Program Files (x86)\Windows Kits\10\tools\{arch}\SecureBoot\EnableSB. {arch} can be one of {amd64, x86, arm, arm64}. The policies are located under the same SecureBoot directory:C:\Program Files (x86)\Windows Kits\10\tools\{arch}\SecureBoot\Policies.

Enable support for the preproduction WHQL/WHCP Signature

Once your driver is preproduction signed, you're ready to provision a test computer where you install the driver.

The provisioning tools and payload are provided starting in Windows 11, version 22H2.

Use of the EnableUefiSbTest tool is recommended. Alternatively, you can manually provision the Microsoft Test Root key from the HLK Secure Boot Manual Tests section (UefiSecureBootManualTests.zip\ManualTests\certs\test\db_MSFTtestSigningRoot.cer). The Microsoft test key must be included in the Secure Boot database (DB) and the Secure Boot Configuration Policy (SBCP) to enable trust for the preproduction WHQL/WHCP driver signature.

Note

When provisioning any of the Secure Boot databases, never production sign a payload with the Microsoft test keys inside.

Provisioning Steps

In the system's UEFI menu, disable Secure Boot and clear the Secure Boot keys, if applicable. This allows the provisioning tool to set the test keys to trust the Secure Boot policy file and re-enable Secure Boot.
Download the correct Secure Boot policy .p7b file, depending on the system architecture, and the accompanying provisioning tool, EnableUefiSbTest.exe, from the WDK. For the location of the provisioning tool, see Prerequisites.
Run the following command in an elevated instance of PowerShell or Terminal and validate that the PK, KEK, db, dbx, and OemId values are empty ("Not Found"):
```
EnableUefiSbTest.exe /dump
```
If Secure Boot is disabled and the keys are successfully cleared, the following output is expected:
```
EnableUefiSbTest.exe /dump

Name: PK
Not Found

Name: KEK
Not Found

Name: db
Not Found

Name:dbx
Not Found

Name: OemId
Not Found
```
Provision the Secure Boot test keys into the Secure Boot db and re-enable Secure Boot by running the following command in an elevated instance of PowerShell or Terminal:
```
EnableUefiSbTest.exe
```
Note

EnableUefiSbTest.exe will not output/return anything after successfully running.

Optionally, specify the thirdparty command to provision the Microsoft UEFI CA certificate alongside the default keys in the Secure Boot DB. This allows trust for Microsoft UEFI CA-signed EFI executables like option ROMs and non-Windows bootloaders.
```
EnableUefiSbTest.exe /thirdparty
```
For devices running Desktop-based Windows, mount the EFI partition of the system and copy over the Secure Boot policy (.p7b) file to S:/EFI/Microsoft/Boot by running the following command in an elevated instance of PowerShell or Terminal:
```
mountvol s: /s
copy-item <path_to_p7b> S:/EFI/Microsoft/Boot/SecureBootPolicy.p7b
```
Note

Because Windows kernel requires the Secure Boot policy file in the form of SecureBootPolicy.p7b, the name and file format must not be modified.
For devices not running Desktop-based Windows, copy the corresponding PreProductionPolicy.pol to \EFI\Microsoft\Boot\Policies. Then delete FullDebugPolicy.pol from \EFI\Microsoft\Boot\Policies.
Reboot the system to allow Windows kernel to refresh the policies. Secure Boot is now re-enabled and provisioned automatically by the provisioning tool. This can be validated by rerunning EnableUefiSbTest.exe /dump as admin and validating that only the dbx and OemId values are empty ("Not Found").
The system is ready to validate preproduction WHQL/WHCP signed driver content. Rebooting the system won't affect the state of the device, as long as the Secure Boot keys and Secure Boot policy files aren't modified.

Deprovisioning Steps

To deprovision the system and opt-out of preproduction signing trust on the system:

Delete the Secure Boot policy files from the mounted EFI partition by running the following commands in an elevated instance of PowerShell or Terminal:
```
mountvol s: /s
rm  S:/EFI/Microsoft/Boot/SecureBootPolicy.p7b
```
Note

If the validations are being performed on a HoloLens 2, the .pol policy files must also be removed from S:/EFI/Microsoft/Boot/Policies.
Boot into the system's UEFI menu and reconfigure Secure Boot keys to factory settings.
Reboot the system and run EnableUefiSbTest.exe /dump, which should return nonempty values for PK, KEK, db, and dbx values indicating the keys were returned to factory state.

Note

We recommend clean installing Windows on the system to de-provision a system intended for retail environments.

FAQs

Q: The EnableUefiSbTest.exe /dump command is only showing a result for PK. Is something wrong?

A: This happens if the tool is run as a standard user instead of as admin.

Q: The EnableUefiSbTest.exe /dump command returns an error that I don't recognize. What do I do?

A: An error may be thrown by the tool when Secure Boot hasn't been successfully disabled and/or the Secure Boot keys haven't been cleared. Verify that Secure Boot is disabled.

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