This is a loosely structured "tutorial" (but really only useful if you know what you're doing) for installing Windows 10 on MacBookAir4,2 (but will probably work on other relatively old models as well), because all other methods hanged the machine at some point (including OpenCore) and I haven't seen it described elsewhere.
The MacBook's internal drive broke down and I needed to install Windows after replacing it, preferably without having to install macOS first just to remove it later -- I don't have much disk space to lose.
I have verified that this instruction works for tiny10, so that's good, and the default Windows 10 build probably works as well, but I prefered something lightweight, so that's what I went with.
My main machine runs Linux, but you can probably repeat the same instructions under Windows. I didn't want to install Windows twice so I found Linux tool replacements for everything I needed.
This Mac's bootloader cannot boot from UDF for whatever reason, so just dding the ISO to a USB flash drive won't work. You need to format the flash drive to FAT and copy all the files from the ISO by hand. I just mounted the ISO as a loop device and used cp.
If you're using the official build, your install.wim file will be larger than 4 GiB and FAT won't accept it. You'll need to use wimsplit from wimlib (available as an official Arch package) to split it into several parts. Copy everything except install.wim to the USB flash drive and do something like
$ wimsplit $MOUNTED_ISO/sources/install.wim $TEMP_DIR_ON_FAST_LOCAL_DISK/install.swm 3000
<wait for the split to finish>
$ cp $TEMP_DIR_ON_FAST_LOCAL_DISK/* $DISK/sources
<wait for the copy to finish>The reason why splitting the file into a temporary directory and then copying it is faster than splitting directly is unclear to me. Obviously the former introduces a sequence of smaller writes to a slow device, but disk cache should have resolved that. If you don't care that much about time spent or don't have enough space on the local disk, just split it directly to the destination.
Your Windows build might have a install.esd file instead of install.wim -- these are usually below 4 GiB so you should be fine. If not, wimlib can probably split them as well, but Ihaven't tried.
You can now eject the USB, but don't forget to sync beforehand.
You can now boot to the installation media, but don't press "Install now" now or ever. That won't work.
Windows 10 (10 in particular, not 7) does not work correctly if booted via UEFI on this device. I haven't been able to figure why this happens, but I'm too tired for further research. If I'm missing something obvious, please tell me. The symptom here is that installation succeeds, but after rebooting to finish the install, Windows just hangs during the bootloader stage: the cyan Windows icon on the black background is shown, but no progressbar appears however long you wait. Pressing F8 does not work either.
So what we'll do is install Windows in CSM mode. We've booted the USB in UEFI mode (and I have no idea how to boot it in CSM/legacy mode, at least when setting it up from Linux, given that booting from UDF didn't work), and Windows cannot install as CSM when booted via UEFI, so we'll take matters into our own hands.
Press Shift+F10 to open the command line. This is the recovery environment, so many commands won't work, but we'll manage.
Start diskpart, use list disk and select disk N to choose the disk we'll be installing Windows to.
We need to ensure MBR is used at this step instead of GPT because AFAIK the Windows bootloader cannot be installed to a GPT disk. list disk should have told you if it's GPT or MBR. If it's MBR, convert it to MBR by running convert mbr. This will fail if there are already any partitions (list partitions) -- you can remove them with clean. This action is obviously destructive, so if you want to retain data, you'll need to find another way to convert the disk. Booting a Linux-based live USB (e.g. Ubuntu works and even installs perfectly fine in UEFI mode, btw; but you'll still need to create a FAT partition manually instead of dding the UDF image) and using fdisk/gdisk works, and you can probably figure something out if you want to keep this tutorial Windows-only as well.
Now we'll create three partitions like in this MSDN tutorial:
create partition primary size=100
format quick fs=ntfs label=System
assign letter=S
active
create partition primary
shrink minimum=650
format quick fs=ntfs label=Windows
assign letter=W
create partition primary
format quick fs=ntfs label=Recovery
assign letter=R
set id=27Quit diskpart with exit or ^C.
We are now ready to flash the image. Find the installation volume with install.wim (it's D: in my example) and run:
dism /Apply-Image /ImageFile:D:\sources\install.wim /Index:1 /ApplyDir:W:\Replace install.wim with install.wsm or install.esd if that's what the file is called in your image.
Now we can add the installation to BCD and initialize the bootsector of the system partition and the disk:
bcdboot W:\Windows /s S: /f BIOS
bootsect /nt60 S: /mbrInitialize the recovery partition and tell Windows about it:
md R:\Recovery\WindowsRE
copy W:\Windows\System32\Recovery\winre.wim R:\Recovery\WindowsRE\winre.wim
W:\Windows\System32\reagentc /setreimage /path R:\Recovery\WindowsRE /target W:\WindowsYou can now reboot with wpeutil reboot and your Windows should probably boot. It'll probably ask you to press a button if you want to skip disk check, do that.
When Windows asks for various info like the Wi-Fi password, proceed as usual. At some point after that, your screen will suddenly turn to black. Don't worry -- it will turn back on in a dozen seconds. Windows has just downloaded the GPU driver and is currently reinitializing the display.
At this point, Windows should work, but right-clicking with your touchpad won't, and audio won't work either, because you're missing drivers. You can install some of them by hand, but the only way to make right-clicking work seems to use Boot Camp, so that's what we'll install.
The problem with Boot Camp is it usually requires macOS to set up, and we only have Windows. So we'll kinda have to simulate what Boot Camp Assistant is doing by hand. You might try to use brigadier to download the Boot Camp setup utility, but brigadier is broken. Apple does not release a simple model-to-image mapping, so brigadier has to find the correct image by filtering a list of all images. There are two images that match the criteria, and by pure chance, brigadier chooses the wrong one that only works on Windows 7. brigadier is written in Python 2, so I can't be bothered to fix it, so we're going to struggle with this step for a bit.
What we're going for here is (hopefully you can do this from another device instead of struggling on the laptop without right click):
- Open this sucatalog file.
- Look for every product that contains
BootCampESD.pkgin the package list. There are currently 32 such products. - Download all distributions (
.English.dist) for these products. grepthe.distfiles byMacBookAir4,2(or whatever your model is, use the "System Information" utility to find it).- Download the
BootCampESD.pkgfor all products that match.
For example, for MacBookAir4,2 in particular, this list currently amounts to (March 2025):
- http://swcdn.apple.com/content/downloads/26/08/041-84821-A_AMCFPC3QDK/4fffs8qgdflw7pn1finqqd40gifh41mvs6/BootCampESD.pkg <- this is the one we're looking for, but you can't really know that without trying both
- http://swcdn.apple.com/content/downloads/29/62/041-84859-A_GGUOSJMIGN/sb1apxcjpp358ze2df6bzhwd49m2cqyzy5/BootCampESD.pkg
You can now download these files, unpack them with 7z x, unpack the Payload~ file with 7z x again, then unpack the extracted file Library/Application Support/BootCamp/WindowsSupport.dmg with 7z x again.
The working package is the one containing only $WinPEDriver$, BootCamp, and AutoUnattend.xml. The broken package contains autorun.inf, BootCamp.xml, BootCamp64.xml, Boot Camp Installation & Setup Guide.pdf, Documentation, Drivers, and setup.exe.
Copy all the extracted files (including $WinPEDriver$!) with the exact same directory hierarchy to Mac and run BootCamp\setup.exe. At some point during installation, your display will blink again. A few features won't work until reboot (e.g. audio or brightness controls), so reboot when you're ready.
We are now ready to fix the trackpad. Open Control Panel, search for "Boot Camp", and enable "Secondary Click" (and other options if you want to) in the "Trackpad" section.
You can tune trackpad scroll sensitivity by changing the "Choose how many lines to scroll each time" option in mouse settings.
You might also recognize that brightness controls do not quite work, and the screen might look too dim. You need to disable the "Change brightness automatically when lightning changes" option in the modern "Display" settings page to fix this.
To reverse scroll direction, follow this tutorial.
The "Shift" key position is my pet peeve. On this laptop, my fingers always try to press the "ISO extra key" instead of left shift, so I use SharpKeys to remap it.