Running Windows 11 on Raspberry Pi 5: Setup, GPIO Code, and Debugging

Running Windows on a Raspberry Pi in 2026 is no longer a novelty—it is a viable edge-computing strategy, provided you use the right hardware and the correct OS variant. The direct answer for a functional Windows build is the Raspberry Pi 5 (8GB variant) running Windows 11 IoT Enterprise LTSC. Standard desktop Windows 11 ARM64 (via the WoR project) is usable but lacks the hardened GPIO driver support and long-term servicing channels required for reliable embedded control. If you are building a kiosk, an industrial HMI, or a .NET-based IoT edge node, Windows IoT on the Pi 5 is the benchmark.

The Decision Matrix: Should You Run Windows on Pi?

Before flashing an image, run your project requirements through this decision path. Do not force Windows onto a Pi if Linux solves the problem more efficiently.

Project Requirement	Recommended Platform
Need full desktop Office, heavy web browsing, or x86 emulation?	Buy an Intel N100 Mini PC. The Pi 5 ARM chip will bottleneck.
Need low-level real-time robotics, ROS 2, or minimal RAM overhead?	Stick to Raspberry Pi OS (Bookworm) or Ubuntu Server.
Need a C#/.NET enterprise edge node with Active Directory and familiar IT management?	Pick: Raspberry Pi 5 (8GB) with Windows 11 IoT Enterprise LTSC.

Hardware Spec Sheet & Parts List

Windows 11 is unforgiving on storage I/O and RAM. The 4GB Pi 5 will thrash the pagefile and stutter; the 2GB variant will not boot. Furthermore, running Windows on a microSD card will destroy the card's NAND cells within weeks due to constant telemetry and pagefile writes. You must boot from NVMe.

Flashing Windows 11 IoT and the NVMe Boot Rule

Microsoft provides official FFU (Full Flash Update) images for the Pi 5 via the Windows IoT Enterprise documentation. Here is the exact sequence to get it running on the NVMe drive.

1. Assemble the PCIe HAT: Mount the Geekworm X1001 on the Pi 5's PCIe FFC connector. Ensure the ribbon cable is seated fully and the latch is locked.
2. Enable PCIe Boot: Before installing Windows, temporarily boot Raspberry Pi OS from an SD card. Open a terminal and run sudo rpi-eeprom-config --edit. Change BOOT_ORDER=0xf41 to BOOT_ORDER=0xf416 to enable NVMe boot priority. Save and reboot.
3. Flash the FFU: Use the Windows IoT Core Dashboard or the ffu2sd tool on a Windows host PC to write the official Pi 5 Windows 11 IoT Enterprise LTSC FFU image directly to the NVMe drive (you can connect the NVMe to your PC via a USB-C enclosure for this step).
4. First Boot: Insert the NVMe drive into the Pi 5 HAT, connect the 27W PSU, and boot. The first boot will take up to 8 minutes as Windows provisions the ARM64 drivers and expands the partition.

Pin Mapping: Linux BCM vs. Windows IoT Headers

When writing code for Windows IoT on the Pi 5, the .NET System.Device.Gpio library uses the BCM (Broadcom) logical pin numbering by default, not the physical header pin numbers. Misunderstanding this is the #1 cause of 'nothing happens' bugs.

Physical Header Pin	BCM Logical Pin (Use in Code)	Function / Notes
Pin 12	BCM 18	Hardware PWM0 (Ideal for relay/motor control)
Pin 16	BCM 23	General Purpose I/O
Pin 18	BCM 24	Hardware PWM1
Pin 3	BCM 2	SDA1 (I2C Data) - Requires pull-up
Pin 5	BCM 3	SCL1 (I2C Clock) - Requires pull-up

The Build: .NET 8 GPIO Relay Controller

The following C# code targets the Raspberry Pi 5 (8GB) running Windows 11 IoT. It uses the official System.Device.Gpio NuGet package (.NET 8). It includes robust error handling to prevent pin-locking if the application crashes.

using System;
using System.Device.Gpio;
using System.Threading;

namespace PiWindowsGpio
{
    class Program
    {
        // Target: Raspberry Pi 5 (8GB) running Windows 11 IoT Enterprise LTSC
        // Physical Pin 12 maps to BCM 18
        const int RELAY_PIN = 18; 

        static void Main(string[] args)
        {
            Console.WriteLine($"Initializing GPIO Controller on BCM Pin {RELAY_PIN}...");
            
            // PinNumberingScheme.Logical means we use BCM numbers, not physical header numbers
            using GpioController controller = new GpioController(PinNumberingScheme.Logical);
            
            try
            {
                controller.OpenPin(RELAY_PIN, PinMode.Output);
                controller.Write(RELAY_PIN, PinValue.Low); // Ensure relay starts OFF (Active Low)

                Console.WriteLine("Starting 10-second pulse cycle. Press Ctrl+C to exit.");

                while (true)
                {
                    controller.Write(RELAY_PIN, PinValue.High); // Relay ON
                    Console.WriteLine("[STATE] Relay Energized");
                    Thread.Sleep(2000);

                    controller.Write(RELAY_PIN, PinValue.Low);  // Relay OFF
                    Console.WriteLine("[STATE] Relay De-energized");
                    Thread.Sleep(8000);
                }
            }
            catch (System.IO.IOException ex) when (ex.Message.Contains("already in use"))
            {
                Console.WriteLine($"FATAL: {ex.Message}");
                Console.WriteLine("The kernel believes this pin is held by a zombie process. Reboot the Pi.");
            }
            catch (System.PlatformNotSupportedException ex)
            {
                Console.WriteLine($"FATAL: {ex.Message}");
                Console.WriteLine("GPIO driver missing. Ensure you are running Windows IoT, not standard Win11 ARM.");
            }
            finally
            {
                // Critical: Always close the pin to release the kernel latch
                if (controller.IsPinOpen(RELAY_PIN))
                {
                    controller.Write(RELAY_PIN, PinValue.Low);
                    controller.ClosePin(RELAY_PIN);
                    Console.WriteLine("Pin safely released.");
                }
            }
        }
    }
}

Debugging: 'The pin is already in use' & Boot Failures

When working with Windows IoT on ARM64, the GPIO driver stack behaves differently than the Linux sysfs or libgpiod stacks. If your application crashes, the Windows kernel may retain the pin lock.

Ranked Causes:

1. Zombie .NET Process: You stopped debugging in Visual Studio or killed the terminal without letting the finally block execute. A background dotnet.exe instance is still holding the pin.
2. Windows IoT GPIO Service Conflict: A background UWP service or Windows IoT Core startup app has claimed the pin in the device manifest.
3. Driver Latch Failure: The bcm2712 GPIO driver in Windows experienced a fault and failed to release the hardware register upon process termination.

The First 3 Things to Check When It Fails:

1. Check Task Manager: Open Task Manager (Ctrl+Shift+Esc), go to the Details tab, and kill any lingering dotnet.exe or your app's executable. This releases 90% of pin-lock issues instantly.
2. Verify Device Manager Drivers: Open Device Manager and expand System Devices. Ensure the Broadcom BCM2712 GPIO Controller is present and lacks a yellow warning triangle. If it is missing, you are likely running standard Windows 11 ARM64 instead of the IoT LTSC build.
3. Hard Reboot: If killing the process fails, the kernel register is latched. Do a full restart (Start -> Power -> Restart). Do not just log out.

Extending and Simplifying the Build

Once the basic relay pulse is verified with a multimeter across the relay's NO/COM terminals, you should adapt the architecture for production.

How to Simplify:
If you only need to trigger a single relay based on a time schedule, abandon the custom .NET code entirely. Use the built-in Windows Task Scheduler combined with a simple PowerShell script invoking the Get-GpioPin cmdlets (available in the Windows IoT PowerShell module). This removes the .NET runtime overhead and reduces RAM usage by ~40MB.

How to Extend:
To turn this into a true edge node, integrate the MQTTnet NuGet package. Wrap the GPIO control logic inside an MQTT message handler. This allows a central Home Assistant or Azure IoT Hub instance to publish a payload like {"pin": 18, "state": "HIGH"}, which the Pi 5 parses and executes locally. Ensure you register the .NET application as a Windows Service using the sc create command so it survives user logouts and boots headlessly.