The following is an alternate tutorial for installing and running Windows 10 on the Raspberry Pi 4. This version concentrates on running Windows from a single USB drive plugged on one of the rear USB 3.0 ports, which is both much faster than other methods and does not require the use of a micro SD card at all.
This guide is provided “AS IS”, with NO WARRANTY that it will work for your specific environment or even that you may not end up losing important data as a result. Therefore, by using this guide, you accept that the responsibility for any software or hardware damage is entirely with YOU.
Also, though perfectly legal (since nothing in the licensing terms for Microsoft Windows prevents you from installing it on a Pi and you can download the Windows 10 ARM64 installation files straight from Microsoft), this method of installing or running of Windows on a Raspberry Pi, is NOT endorsed by Microsoft or the Raspberry Pi Foundation. If you choose to follow this guide, you accept that Microsoft and the Raspberry Pi Foundation do not bear any liability with regards to the behaviour of Windows on the targeted platform.
By following any of the steps below, you implicitly acknowledge that you have read these conditions and have agreed to them.
A Raspberry Pi 4 where the EEPROM is up to date enough to allow straight to USB boot. If you purchased a Pi 4 recently, this should already be the case, but if not (i.e. if you find that your machine cannot boot from USB) then you should download a recent version of a rpi-boot-eeprom-recovery archive from here, put all the files on a MBR-partitioned, FAT32-formatted SD card, and apply the update.
A fast USB 3.0 drive, with a capacity of at least 32 GB, such as a fast flash drive (please use a drive that has a write speed greater than 50 MB/s, and that also have a sufficient random I/O speed, as your experience will be greatly diminished otherwise), a USB 3.0 SSD enclosure, etc.
Screen, keyboard, mouse & a powerful enough PSU.
As mentioned above, you will notice that no microSD card is used when following this guide (provided that your EEPROM is recent enough).
A Windows host machine to create the drive, since this guide uses Windows-only utilities.
A Windows 10 for ARM64 ISO or install.wim. At this stage, we recommend to use the feature update to Windows 10, version 2004 (19041.330), as other releases, and especially more recent ones, are known to have broken the ability to boot from USB. Because Microsoft does not yet publish retail ARM64 ISOs, like they do for x86 or x64, you need to use a third party utility to create one, such as the one from https://uupdump.ml/. In this case, you want to use this direct link to download the script, allowing you to create the required 19041.330 installation media.
Plug in your target USB 3.0 drive. It is recommended that you unplug any other USB media, such as flash drives or USB HDDs, so that you don’t end up erasing them by mistake
Run WoR.exe and select your language. Note that the language you select for WoR has no effect on the language Windows will be installed into, which is dependent on your source image.
Select your device in the dropdown (again, make sure you do select the right device as internal drives may be listed!) and select Raspberry Pi 4 [ARM64] for the other option.
On the Select your Windows on ARM image, pick the .iso/.wim/.esd/.ffu for the Windows 10 image you want to install, which you obtained in the Software Requirements. If needed wait for the image to be mounted and then select the edition you would like to install.
On the Select the drivers screen, choose the option that is suitable for you (most likely Use the latest package available on the server if you haven’t already downloaded the drivers).
On the Select the UEFI firmware, choose Use the latest firmware available on the server, as you will need the most up to date official UEFI firmware for USB boot.
On the Configuration screen validate that everything is in order and click Next (Don’t change the General configuration options unless you know what you are doing). Especially, make sure to double check that the Target device being listed is really the drive you want to use on your Raspberry Pi, and press Install.
Wait for the installation to finish. Note that if that process takes more than 25 minutes to complete, it means that the drive you are trying to use is slow and will probably result in a poor Windows experience. In other words, the longer you spend creating the drive, the more likely it is that Windows will perform poorly.
Remove the USB and plug it to one of the USB 3.0 ports of your Raspberry Pi 4 (make sure that it is one of the blue USB 3.0 ones). Windows should boot, go through the finalization stage of the installation process (it should reboot once), and let you log on after going through the various installation screens.
If you have a 4 GB or 8 GB model, you will find that the RAM is limited to 3 GB by default. To enable the whole RAM, you will need to go to the UEFI settings (Esc key during boot) and then go to Device Manager → Raspberry Pi Configuration → Advanced Configuration and set Limit RAM to 3 GB to <Disabled>. Then save your settings and reboot.
ESP support. This means that you can now place your Pi 4 boot files into a EFI System Partition, and have the UEFI firmware launch as expected, regardless of whether you are using an MBR or GPT ESP, or even of the ESP resides on a USB or SD. Of course, this feature doesn’t really come from the UEFI firmware itself, that has always supported it, but from the firmware archive containing an updated start4.elf from the Raspberry Pi Foundation, where ESP boot support has finally been added.
Note that booting from USB or from ESP does require a recent-enough version of the Pi EEPROM.
This is a minor release, but the asset tag functionality is pretty cool. This let’s you set a custom string to be reported via SMBIOS to the booted OS, which you could use for inventory or provisioning requirements.
The tag can also be set programmatically or via the UEFI Shell command line.
The 8GiB variant changes the board layout a bit, dropping the SPI EEPROM containing the xHCI (USB3 controller) microcode, which required the relevant code to be added to UEFI to load it during boot. The good news is that the same approach is harmless on the other (1GiB, 2GiB and 4GiB Pies).
Like the 4GiB variant, UEFI will default to booting with only 3GiB to deal with OSes that can’t process the ACPI-reported DMA limits.
Of course, without the 3GiB limit, you get the full 8GiB (minus the gpu_mem amount anyway).
Booting to UEFI Shell should be a bit less awkward now, now that it is permanent to the Boot Manager menu.
So, the Pi 3A+ is finally documented as being supported. It involved no code changes and is the cheapest Pi you can run the 64-bit UEFI firmware on.
But there’s more – the work to automatically support booting via PL011 and miniUART serial ports, done by Pete Batard on the UEFI side and Andre Przywara for TF-A, finally means we can boot on boards where PL011 is used to expose the serial port. The Pi 2B (v1.2) is one such board – the slowest member of the 64-bit UEFI for Pi family. It’s basically a Pi 3 without WiFi, BT and worse heat dissipation, so it is clocked down.
And after fixing a small eMMC support regression, we even support the compute module variant of the Pi 3. To be fair, I didn’t test the CM3L (the one without eMMC), but it should be working. Let me know if it doesn’t. Also, CM3+ (which just has better heat dissipation) should work but is not validated.
And in case you’re a fan of the amazing cluster carrier board from our friends over at miniNodes…
Those last two fixed regressions seen on Windows 10 after some ACPI restructuring to properly describe DMA constraints on VideoCore-attached devices. The regressions affected Pi 3, but the fix should equally apply to Pi 4.
TF-A is the Arm secure firmware, providing services such as platform power off/reset and secondary CPU manipulation. The improvements to UART detection mean that TF-A firmware, just like UEFI, will honor config.txt selection of the UART (e.g. via overlay, although it’s really done by the VPU firmware). This is more developer oriented, and means not losing logging/initialization messages. Unrelated to Pi 4 itself, it paves the way for proper (transparent) Pi 3 UEFI support for Compute Module variants and that 64-bit variant of the Pi 2 (rev 1.2).