Windows 10 build 10586.1078 (th2 bnb arm64)

Windows 10 build 10586.1078 (th2_bnb_arm64) is an internal post-RTM build of Windows 10 November Update, which was found on a Qualcomm Snapdragon 810 (MSM8994) Large Interface Qualcomm User Interface Device (LIQUID) Reference Platform. Several screenshots of this build in the ARM64 architecture and the CoreARM SKU running in the QEMU emulator were posted on the BetaWiki Discord server on 2 February 2025, followed by its ntoskrnl.exe and its Recovery Environment WIM shortly after. The full build was shared on 17 February 2025.
This build notably features an early version of the x86-to-ARM (XtA) JIT compiler, which allows running certain x86 applications, and is the earliest known client build of Windows on ARM64 to feature the full desktop experience.
Unlike most other Windows 10 November Update builds, this build uses test code signing and as a result can be booted on the current date.
== Installation ==
=== Prerequisites ===
The following requirements used in order to install this build onto a virtual machine are listed below:
*A 64-bit version of QEMU
*A version of the TianoCore EDK II firmware for ARM64 emulation, to be placed in the QEMU installation directory under fw/QEMU_EFI.fd
*The Red Hat VirtIO driver package
*Virtual hard disk image for OS install
=== Instructions ===
Create the needed virtual disk images through the diskpart utility by running the below script; they will be created under a directory in the C: drive named 10586ARM64. The partitions it will contain will be respectively mounted under drive letters P and Z.
create vdisk file="C:\10586ARM64\HDD.vhd" maximum=65536 type=expandable
select vdisk file="C:\10586ARM64\HDD.vhd"
attach vdisk
convert gpt
create partition efi size=100
format quick fs=fat32
assign letter=Z
create partition primary
format quick fs=ntfs
assign letter=P
exit
Deploy the WIM image, mount the VirtIO driver disc image, install the Windows 10-specific VirtIO storage driver by invoking the following DISM commands and add the boot files to the EFI partition:
rem Apply the image and install the VirtIO storage driver (both install_NoCustomizations.wim and install_WithCustomizations.wim will work fine)
DISM /Apply-Image /ImageFile:"X:\path\to\install_NoCustomizations.wim" /ApplyDir:P:\ /Index:1
DISM /Image:P:\ /Add-Driver /Driver:"Y:\viostor\w10\ARM64\viostor.inf"
rem Make system bootable
bcdboot "P:\Windows" /s Z: /f UEFI
Eject the currently attached virtual disk from the machine, then paste and run the contents of the below script onto a batch file within the QEMU installation directory:
set MAIN="C:\10586ARM64\HDD.vhd"
qemu-system-aarch64 ^
 -M virt,highmem=false -cpu cortex-a72 -smp cores=4,threads=2 -m 2048 ^
 -device qemu-xhci -device usb-kbd -device usb-tablet ^
 -hda %MAIN% ^
 -bios fw\QEMU_EFI.fd -device ramfb ^
 -rtc base=2016-01-24,clock=vm ^
 -device intel-hda device hda-output ^
 --accel tcg,thread=multi
==Bugs and quirks==
=== Recovery Environment ===
The Recovery Environment launcher (RecEnv.exe) is broken and will crash out with an error in this build. It is possible to bypass the error by modifying winpeshl.ini in the WinRE image to point to the Command Prompt (X:\Windows\System32\cmd.exe), which will make it act more like a WinPE by launching the Command Prompt instead of the broken recovery tools.
== Readme ==
The build was shared along with the following readme:
==Gallery==
win8boot.png|Boot screen
===Full build===
====Screenshots shared prior to publication====
10586desktop.png|Desktop with Winver
10586pdb.png|Debugging symbols
10586-startmenu.png|Start Menu
10586-firefox.png|Firefox running under x86 emulation
10586-minecraft4k.png|Minecraft 4k with Java running under x86 emulation
===Recovery Environment===
10586winrebug.png|Error when loading Windows RE
10586.png|Windows RE modified to open Command Prompt
===Reference Device===
File:Win10-10586-bnb-RefDev1.png
File:Win10-10586-bnb-RefDev2.png
Category:Windows 10 November Update builds
Category:Windows 10 builds