Spark eGPU

Run an external NVIDIA GPU (eGPU over USB4/Thunderbolt) on a Windows on ARM laptop with an NVIDIA RTX Spark (N1X), such as the HP OmniBook, by binding the Spark's own ARM64 NVIDIA driver to the eGPU and applying the RM1774520 Code 43 workaround. Optional connect-time automation re-applies this whenever the eGPU shows up.

Warning

• This is an unsupported driver binding. NVIDIA does not ship an ARM64 driver for desktop GPUs; the Spark driver is forced onto a device it does not list.
• A display interruption, driver crash, or system crash is possible.
• Shut down Windows before unplugging the eGPU or powering off its enclosure. Hot-unplugging an RTX 3090 on driver 621.14 has caused VIDEO_DXGKRNL_FATAL_ERROR (0x113) on this HP setup. Passing PnP and nvidia-smi checks does not establish safe hot-removal.
• No security settings are changed (no test signing, no Secure Boot or driver signature changes, no INF edits). Nothing is downloaded.
• Use at your own risk. Read the scripts before running them elevated.

Connecting

• Supported order: shut down Windows, boot, log on, then plug in the eGPU. A cold boot with the eGPU attached is not possible with the AOOSTAR AG02.
• Each USB4 port gives the eGPU its own device instance, so the first connect on a new port needs one bind. The automation does this on connect.
• Code 43 can return on a later connect even with RM1774520=1 set. Restarting only the eGPU (-Mode Restart, or automatically once per boot) has cleared it.

Tested hardware

Reports from the Level1Techs thread. All on an HP OmniBook X 14-ks000 over USB4.

eGPU	Dock	Driver	Result
RTX 4070	AOOSTAR AG02	621.01	Working after RM1774520=1
RTX 3090 (MSI)	AOOSTAR AG02	621.14	Working: hot-plug after logon on both USB4 ports; 10 min gaming load with no TDR/Xid; CUDA kernel OK (809 GB/s device bandwidth); Cyberpunk 2077 benchmark 76.72 FPS average. Code 43 sometimes returns, cleared by restarting the eGPU
RTX 5090	-	621.14	Code 12 (PCIe BAR placement); no fix known
NVIDIA A2	-	-	Code 43 persists with RM1774520=1

Requirements

• Windows 11 ARM64 laptop with an NVIDIA RTX Spark GPU, with NVIDIA's ARM64 Spark driver already installed and healthy on the internal GPU. The scripts never download, extract, or install driver packages; they reuse the one in the driver store.
• Built-in Windows PowerShell 5.1 or PowerShell 7, running natively on ARM64.
• Administrator rights for any change. Inspect and -WhatIf need none.

Quick start

Get the scripts, then unblock them (files downloaded from the internet are blocked):

git clone https://github.com/thatguywob/RTX-Spark-eGPU
cd RTX-Spark-eGPU
Get-ChildItem *.ps1, *.psm1 | Unblock-File

Or download a release ZIP, extract it, and run the Unblock-File line in that folder.

Connect the eGPU, then from this folder:

# Read-only: internal Spark, each external NVIDIA GPU, the model that would be bound,
# and the pending action.
.\Configure-SparkEgpu.ps1

# Dry run.
.\Configure-SparkEgpu.ps1 -Mode Install -WhatIf

# From an elevated PowerShell: back up, bind, and apply the Code 43 fix if needed.
.\Configure-SparkEgpu.ps1 -Mode Install -AcceptUnsupportedBinding

If the execution policy blocks scripts:

powershell -ExecutionPolicy Bypass -File .\Configure-SparkEgpu.ps1 -Mode Install -AcceptUnsupportedBinding

The scripts act on every present NVIDIA PCI display device that is not the internal Spark. With more than one, pass -InstanceId (shown by Inspect).

What Install does:

1. Checks the internal Spark is healthy on a signed OEM driver package.
2. Picks the Spark model from that package, preferring the internal GPU's exact matching hardware ID. Identically named models remain separate during enumeration; a unique same-section/device-family candidate is used only if no exact match exists. Binds it to the eGPU with DiInstallDevice.
3. If the eGPU then reports Code 43, sets RM1774520 (DWORD 1) in its driver key and restarts the device.
4. Checks the internal Spark and NPU are still healthy and that nvidia-smi lists the eGPU. If a previously healthy sibling disappears or changes problem code or INF, the error identifies the device and its before/after state.

Every change first saves state.json plus registry exports for Restore.

Inspect, Install, and Auto report the internal GPU's published and original driver-store INF paths. They warn about a different eGPU package or a configured nvlddmkm service path outside the internal GPU's package. This is advisory: the service registry path does not prove which driver image is currently loaded, and no package is removed or service setting changed.

Restart, stop, start

From an elevated PowerShell (each supports -WhatIf and -InstanceId):

# Restart the eGPU, e.g. when it boots at Code 43 although already bound; then verify it.
.\Configure-SparkEgpu.ps1 -Mode Restart

# Disable the eGPU. It stays disabled across reboots and automation leaves it alone.
.\Configure-SparkEgpu.ps1 -Mode Stop

# Re-enable a stopped eGPU, then verify it.
.\Configure-SparkEgpu.ps1 -Mode Start

Shutting down Windows before unplugging the eGPU or powering off its enclosure remains the recommended path. Hot-unplug after Stop worked once (RTX 3090, driver 621.14): the cable was pulled with the eGPU disabled, the internal Spark stayed at Code 0, and after replugging into the same USB4 port the device returned with the same instance ID, still disabled (Code 22) and ignored by automation, and Start brought it back healthy. That single test does not establish that hot-removal is safe. Unplugging an eGPU that is still enabled has not been tested. To try it: save your work, run Stop, unplug the cable only, check with Inspect, replug into the same port, then run Start.

Optional mise tasks

With mise installed, mise tasks ls lists every action in mise.toml and mise run <task> runs the matching PowerShell command above (inspect, install, restart, stop, start, restore, automation-auto, automation-prompt, automation-remove, test). Arguments after -- are passed through, e.g. mise run restart -- -WhatIf or mise run restore -- -BackupPath <state.json>. Tasks that change devices or the scheduled task need an elevated terminal. mise is not required.

Automation

Each USB4 port gives the eGPU a new device instance, so moving ports or reinstalling can leave it on the Microsoft Basic Display Adapter again. The scheduled task fixes that on connect. Install it from an elevated PowerShell, picking one mode:

# Prompt: asks the logged-on user, then requests administrator approval (UAC).
.\Install-SparkEgpuAutomation.ps1 -Trigger Prompt

# Automatic: runs as SYSTEM, binds without asking.
.\Install-SparkEgpuAutomation.ps1 -Trigger Automatic -AcceptUnsupportedBinding

# Remove the task and installed scripts (backups and logs are kept).
.\Install-SparkEgpuAutomation.ps1 -Uninstall

• The scripts are copied to %ProgramFiles%\SparkEgpu, so the task never runs a user-writable file. Re-run the installer after editing the scripts.
• Triggers: Kernel-PnP configuration events 400 (device configured) and 411 (problem starting) for Display-class devices only, plus boot (Automatic) or logon (Prompt).
• Automation binds a given device instance to a given Spark driver package once. The result is recorded in %ProgramData%\SparkEgpu\bind-history.json, so a failed bind is not retried on every reconnect and a Restore is not undone. A driver update (new package) allows one new attempt. To retry by hand, run .\Configure-SparkEgpu.ps1 -Mode Install -AcceptUnsupportedBinding. History records each attempt's result (for example Failed, Succeeded, Restored); any recorded result blocks another automatic bind for that device/package. See Logs and backups.
• An eGPU working on a different NVIDIA package is left alone and logged; it may be older, newer, or another OEM's package. Run a manual Install to move it to the internal GPU's current package.
• Code 12 (PCIe resource allocation, seen on the RTX 5090) has no automatic fix.
• A bound eGPU that reports Code 43 with RM1774520=1 already set is restarted once per device per boot (recorded in bind-history.json as <id>|restart|<boot time>). If Code 43 persists, later runs that boot leave it alone: shut down Windows, power-cycle the enclosure, then boot.
• A disabled eGPU (Code 22, from -Mode Stop) is never bound or restarted.

If the Automatic task does not run on your system (for example because Group Policy enforces AllSigned, visible in the log as "is not digitally signed"), sign the scripts or use Prompt mode.

Restore

Each change writes %ProgramData%\SparkEgpu\Backups\<time>-<mode>-<id>\state.json. Restore only accepts backups from that folder.

.\Configure-SparkEgpu.ps1 -Mode Restore -BackupPath "$env:ProgramData\SparkEgpu\Backups\<run>\state.json" -WhatIf
.\Configure-SparkEgpu.ps1 -Mode Restore -BackupPath "$env:ProgramData\SparkEgpu\Backups\<run>\state.json"

• The backup whose state.json has "Rebind": true is the one that restores the driver the eGPU had before binding (usually the Microsoft Basic Display Adapter, which reports Code 10 for these cards: restoring it is not a working-GPU fix).
• Restore needs the eGPU on the same USB4 port as the backup.
• If Windows asks for a reboot, reboot and run the same Restore command again.
• After a Restore, automation will not bind that device to the same package again.

Game GPU preference

Once bound, the eGPU also shows as "NVIDIA RTX Spark N1X", so Windows Settings cannot tell the two GPUs apart by name. Set the preference by hardware ID instead:

.\Set-EgpuGamePreference.ps1 -ExePath 'C:\Games\Cyberpunk 2077\bin\x64\Cyberpunk2077.exe' -WhatIf
.\Set-EgpuGamePreference.ps1 -ExePath 'C:\Games\Cyberpunk 2077\bin\x64\Cyberpunk2077.exe'

This writes SpecificAdapter=<VEN>&<DEV>&<SUBSYS> (for example 10DE&2204&38841462) into HKCU\Software\Microsoft\DirectX\UserGpuPreferences, keeping other settings in that value. No administrator rights are needed. Fully exit and relaunch the game.

An existing GpuPreference is kept. If the game was already set to Power saving (GpuPreference=1) or High performance (2) in Windows Settings, SpecificAdapter may be ignored: set the game back to "Let Windows decide" (or delete its value), then run the helper again. The helper sets a preference; to see which GPU a running game actually uses, watch the sm column per GPU (index from nvidia-smi -L):

nvidia-smi dmon -s u

Logs and backups

Path	Contents
%ProgramData%\SparkEgpu\Backups	state.json and registry exports per change
%ProgramData%\SparkEgpu\Logs	auto-<date>.log transcripts (30 days)
%ProgramData%\SparkEgpu\bind-history.json	One entry per device instance and driver package, plus one per automatic Code 43 restart per boot. Results: Started, Bound (SetupAPI returned successfully), RebootRequired, Failed (bind did not return successfully), VerificationFailed (bind returned but later configuration/checks failed), Succeeded, Restored (rollback). Existing entries are not reclassified
%LOCALAPPDATA%\SparkEgpu\Logs	Prompt mode transcripts
%LOCALAPPDATA%\SparkEgpu\Backups	UserGpuPreferences exports from the game helper

%ProgramData%\SparkEgpu is writable only by SYSTEM and Administrators.

Regression checks

Run the isolated, hardware-free configuration-flow tests in a fresh process:

powershell -NoProfile -ExecutionPolicy Bypass -File .\tests\Configure-SparkEgpu.Tests.ps1

These cover bind failures, reboot requests, sibling disappearance/problem/package changes, NVIDIA enumeration failure, successful verification, the once-per-boot automatic Code 43 restart (success and failure), and leaving a disabled device alone, including history round-tripping and the per-device/package automatic retry guard. Live inspection does not establish CUDA, graphics, or safe hot-removal support.

Reporting results

Open a GitHub issue or post in the Level1Techs thread with:

• Laptop model and BIOS version
• Dock/enclosure and connection (USB4/Thunderbolt port)
• eGPU model and hardware ID (PCI\VEN_10DE&DEV_xxxx&SUBSYS_xxxxxxxx)
• NVIDIA driver version
• Output of .\Configure-SparkEgpu.ps1 (Inspect)
• The relevant lines from %ProgramData%\SparkEgpu\Logs\auto-<date>.log

Credits

• RTX eGPUs working on RTX Spark (HP OmniBook), Level1Techs forum
• Reddit /r/eGPU post 1xekn5m
• AleCyriaco/nvidia-error43-fix
• DiInstallDevice (Microsoft docs)

License

MIT; see LICENSE.