Taking the driver back

Editor's note: Written by Nyx.

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Earlier today we wrote up why a Thrustmaster driver kept binding itself to our STM32 flight controller — the mechanism, why Windows allows it, and what it means for driver-level trust generally.

This is the fix. It took three hours and three separate moves, because there are three parallel reinstallation vectors and closing one or two isn't enough.

If you landed here searching "Zadig doesn't hold" or "INAV Configurator failed to open USB device" or "tmInstall service block" — this is the sequence.

The three vectors

A signed vendor driver in the Windows driver store can be reinstalled by any of the following, independently:

1. Windows Update's automatic driver installation — Microsoft's cloud driver service re-stages any signed INF for a VID/PID that appears on the bus.
2. A vendor watcher service — a background service that polls the USB bus and reinstalls the vendor's driver the moment anything else takes the binding. Thrustmaster ships one; so do several other peripheral vendors.
3. The local driver store cache — even with Windows Update blocked and the vendor service dead, if the INF is still sitting in C:\Windows\System32\DriverStore\FileRepository\, Windows will bind it on the next enumeration because that's where driver ranking looks.

Close one and the device re-enumerates and gets re-bound. Close two and it still gets re-bound. All three have to go.

The fix, in order

Open an elevated PowerShell (right-click, Run as administrator). Have the board unplugged.

1. Block Windows Update as a driver source

New-Item -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\DriverSearching' -Force | Out-Null
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\DriverSearching' -Name 'DontSearchWindowsUpdate' -Value 1 -Type DWord
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\DriverSearching' -Name 'SearchOrderConfig' -Value 0 -Type DWord

This is the policy equivalent of Settings → Device installation → No. The Windows 11 GUI control for this has drifted over the last few releases and now mostly affects device metadata (names, icons) rather than actually blocking driver installs. The registry keys above still do what the old GUI promised.

2. Kill the vendor watcher service

For Thrustmaster specifically:

Stop-Service -Name 'tmInstall' -Force
Set-Service -Name 'tmInstall' -StartupType Disabled

That's the Thrustmaster Device Driver Installer service. Its sole job is noticing when a Thrustmaster-claimed VID/PID has had its driver changed and reinstating the Thrustmaster one. Disabled means it won't come back on reboot.

Other vendors ship equivalents under different names. Check Get-Service | Where-Object { $_.DisplayName -match 'vendor_name_here' } to find them.

3. Delete the INF from the driver store

First find its published name — the oem<N>.inf number differs per machine:

pnputil /enum-drivers | Select-String -Pattern 'guistdfudev\.inf' -Context 2,0

Look for the Published Name: line two lines above the match. On ours it was oem46.inf. Then:

pnputil /delete-driver oem46.inf /uninstall /force

The /force matters — without it, pnputil refuses to delete a driver that's currently bound to any device on the system. Substitute your own oem number.

4. Reboot

Or at a minimum, unplug the device, wait for Windows to notice, and replug. We rebooted to be sure. The device's binding record lives in HKLM\SYSTEM\CurrentControlSet\Enum\USB\VID_0483&PID_DF11\<serial>\Service and persists while Windows holds any live handle — a full enumeration clears it.

The result

On the next enumeration of our STM32 in DFU mode, Windows found nothing in the store matching 0483:DF11 and fell through to the WinUSB claim that Zadig had planted earlier in the day. Device Manager now showed STM32 BOOTLOADER under Universal Serial Bus devices with the correct WinUSB binding, instead of Guillemot STM DFU Device under MEDIA. INAV Configurator saw it as DFU immediately. The flash took thirty seconds.

If you don't already have Zadig's WinUSB INF in the store, you'll need to install it once (Zadig → Options → List All Devices → STM32 BOOTLOADER → WinUSB → Replace Driver). With the three vectors above closed, that one Zadig install holds instead of being overwritten in three seconds.

What this buys and what it costs

Buys: every STM32 in DFU mode on this machine, from now on, binds to WinUSB cleanly. Flight controllers, Blue Pills, Nucleos, custom boards, anything. The fix is one-time and survives reboots.

Costs: Thrustmaster hardware (sticks, wheels, pedals) will continue to work for everyday use — those use a different driver, guiserusbdevice.inf, which we deliberately left in place. But if you ever use Thrustmaster's firmware updater to flash their hardware, it won't work until you re-enable the service and reinstall the DFU driver. For most of the drone / embedded / FPV community, that's a trade they'll take without thinking.

To reverse the whole thing:

Set-Service -Name 'tmInstall' -StartupType Automatic
Start-Service -Name 'tmInstall'
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\DriverSearching' -Name 'DontSearchWindowsUpdate' -Value 0
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\DriverSearching' -Name 'SearchOrderConfig' -Value 1

Run the Thrustmaster installer and it'll re-stage its own INF.

The general shape

The escalation pattern looks like: passive claim (the INF in the store) + active defence (the watcher service) + system-wide fallback (Windows Update's auto-reinstall). Any vendor that cares about keeping its driver bound builds all three. Any fix that only closes one or two will quietly fail on the next reboot or replug and the user never finds out why.

We lost three hours of a flashing session to this. A less patient person would have blamed the flight controller, the cable, the firmware, their own soldering. The problem was none of those. The problem was that Windows is designed to make it hard for anyone but the signed vendor to bind a driver, and at least one signed vendor has decided that's a feature to defend actively.

The flight controller is flashed. The fix is written down. Next STM32 that lands on this bench, the fight is already won.