pi4bdd

Second Monitor Support for Pi4 running Windows 10 for ARM Insider Build 21322
Build output available at: https://github.com/TheMindVirus/pi4bdd/tree/main/KMDOD/ARM64/Release/SampleDisplay

WARNING!

Changing firmware and drivers may make your OS fail to boot.
Please use with caution! (See below for Troubleshooting)

Known Issues

May cause failure to boot for a variety of reasons (and may need multiple restarts)
Black Screen at LogonUI on Windows (which may eventually resolve itself over time)
Mailbox data access is temperamental and is best effort (a restart may help this)
A lot of the DXGK code is messy and unused (additional effort is required to clean this up)
The DXGK Display Only Driver source is not capable of rendering (a separate initialisation is required)
The driver currently only supports 1080p ARGB 32bpp on HDMI1 at variable refresh rate
(This is due to a lot of properties being hard coded in the KMDOD sample driver)
On some monitors you may experience visual glitches (due to formatting and timing errors)

Monitor1

Monitor2

Troubleshooting

When copying the UEFI folder into an existing installation,
Please use your existing EFI folder and take a backup of the BCD file for Windows.
(This is located in X:\EFI\Microsoft\Boot\BCD and can be accessed with bcdedit /store)

Press ESC at boot after Rainbow Splash to Enter UEFI BIOS Settings.
Please make sure your settings match the following:

[Device Manager]
--[Raspberry Pi Configuration]
----[CPU Configuration]
------[CPU Clock]
--------<Custom>
------[CPU Clock Rate (MHz)]
--------<2000>
----[Display Configuration]
------<Native resolution> #NOTE: Selecting 1080p may either work or may cause display overspill
----[Advanced Configuration]
------[Limit RAM to 3 GB]
--------<Disabled> #NOTE: Setting this limit to <Enabled> has worked for some people
------[System Table Selection]
--------<ACPI>
----[SD/MMC Configuration]
------[uSD/eMMC Routing]
--------<Arasan SDHCI> #NOTE: Select <eMMC2 SDHCI> only if you have an eMMC2 OS driver installed
------[uSD Force Default Speed]
--------<Allow High Speed>
------[SD Default Speed (MHz)]
--------<50>