OpenBootCamp

An open-source implementation of some of Boot Camp's keyboard services in C#.

Disclaimers

• This program was developed by using clean-room reverse-engineering techniques, including decompiling Boot Camp services.
• This program, repository and its authors are not affiliated with Apple Inc. in any way, shape, or form.

Features

OpenBootCamp currently implements the following features of Boot Camp Manager:

• Fn behaviour switching: Switch whether the default Fn behaviour should be the standard Fn keys, or the special function printed on each key.
• Special Fn key handling: This includes keys like the display brightness, keyboard brightness, and optical drive eject keys.

Additionally, the following bugs from the official Boot Camp Manager are fixed:

• Keyboard backlight state is not remembered across reboots
• Special Fn keys do not work before login (Apple's Boot Camp Manager doesn't run until a user logs in)

_{along with introducing a whole lot of other bugs/missing features, but still...}

Planned features

Roughly in priority order:

• An overlay when adjusting keyboard backlight, screen brightness, and volume (when not already handled by Windows)
• A config application. Learn to edit XML for now.
• A few power saving features:
  • Turn off keyboard backlight when closing laptop lid (something which I would've thought would be done in hardware/drivers, but here we are)
  • Set keyboard backlight state based on power source or battery charge (e.g. low battery, switching between AC and battery power)
  • Turn off keyboard backlight when keyboard is inactive
• Volume control on older Windows versions (7 and earlier?)
• Smooth keyboard backlight animations
• More that I haven't thought of yet

Supported systems

Only Apple computers that can run Windows are supported (i.e. any Intel Mac). Any non-Apple Windows systems are not supported (even if using a Magic Mouse/Trackpad/Keyboard).

Windows 7 SP1 and later with .NET Framework 4.8 should work without issues.

Windows Vista/XP may work if you downgrade the project to .NET Framework 4.6 (for Vista SP2) or 4.0 (for XP SP3), but are currently unsupported.

Additional requirements

The following drivers are required for OpenBootCamp to work:

• The Apple Keyboard driver (Keymagic.sys) for OSX Fn behaviour switching and enabling display brightness shortcuts on Windows 8 and later.
• KeyAgent.sys for enabling other special Fn keys and for brightness/volume keys on Windows 7 and lower.
• MacHALDriver.sys for keyboard backlight support.

Download

Downloads are currently unavailable.

Please compile the program yourself in the meantime.

Compile

Using Visual Studio

1. Install Visual Studio 2022 with the .NET Desktop Development workload checked.
2. Download the code repository, or clone it with git.
3. Extract the downloaded code, if needed.
4. Open OBC.sln in Visual Studio.
5. Click Build > Build Solution to build everything.
6. Your output, assuming default build settings, is located in OBC.Service\bin\Debug\net48\.
7. ???
8. Profit!

From the command line

1. Follow steps 1-3 above to install Visual Studio and download the code.
2. Open Developer Command Prompt for VS 2022 and cd to your project directory.
3. Run msbuild /t:restore to restore the solution, including NuGet packages.
4. Run msbuild OBC.sln /p:platform="Any CPU" /p:configuration="Debug" to build the project, substituting Debug with Release for a Release build instead.
5. Your output should be located in OBC.Service\bin\Debug\net48\ (or similar).
6. ???
7. Profit!

FAQ

How did you make this?!

By decompiling Bootcamp.exe (located at C:\Program Files\Boot Camp on a Mac running Windows with Boot Camp installed) with Binary Ninja.

I was going to use ghidra, but found Binary Ninja produced more readable pseudo-code.

I will go more in-depth in another document soon.

Why did you make this?

Because I was/am unhappy with the Apple-provided Boot Camp services.

Also, reverse-engineering is fun :D (if you know what you're doing, that is)

How do I install this?

1. Obtain a copy of KeyAgent.sys and MacHALDriver.sys for your laptop (see below).
2. Create a folder in the same location as InstallMgr.exe called BootCamp (if it doesn't exist), and move both files there.
3. Run InstallMgr.exe, and install both KeyAgent.sys and MacHALDriver.sys, then reboot.
4. Run InstallMgr.exe again, then install and run OpenBootCamp service.
5. ???
6. Profit!

NOTE: if you try to uninstall MacHALDriver.sys in the future, it might still show as "Installed" until you reboot. This will be fixed in a future commit.

How do I obtain KeyAgent.sys and MacHALDriver.sys?

1. Download the Boot Camp support software for your Mac using Boot Camp Assistant (or Brigadier if you're already on Windows).
2. Navigate to and open Drivers\Apple\BootCamp.msi in 7-Zip.
3. Copy KeyAgent.sys and MacHALDriver.sys to a folder named BootCamp in the same folder as InstallMgr.exe, then follow the instructions to install them with OpenBootCamp.

While you're at it, install the Apple Keyboard drivers if you haven't already (the installer's called AppleKeyboardInstaller64.exe, and is in the same folder as BootCamp.msi).

My Boot Camp support software has KeyManager.sys, but not KeyAgent.sys?

If you couldn't find KeyAgent.sys, but found KeyManager.sys, your laptop is currently too new for OpenBootCamp. Come back when someone adds support for these laptops.

I won't be able to do this, as I don't have access to a Mac with this configuration.

I want <feature X> in OpenBootCamp!

Ask nicely in the issues, and I might add your feature if I know how, have time, and I think it'll benefit the project.

Alternatively, create a pull request and add the feature yourself.

.NET/Core?

No.

Linux?

Linux already has native support for Apple hardware (at least on the laptops I tested it on), so a Linux port would be pointless.

License and Copyright

Copyright © 2024-2025 Sparronator9999.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.