dudeitssm · October 12, 2022 02:37 · Jun 6, 2018
diff --git a/win10-install-to-external-hdd-using-winpe.md b/win10-install-to-external-hdd-using-winpe.md
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+# Installing Windows 10 to an external drive without a Windows host
+
+## The long story
+
+We were talking at the office about having a LAN Party and playing some old
+school games like Age of Empires and Starcraft. The issue is that I have Linux
+installed. I didn't want to ruin everyone else's fun by having random crashes,
+out-of-sync errors and similar stuff using Wine, and I didn't want to do the
+dual boot dance, so I figured out that the best option was to install Windows to
+an external drive.
+
+I remember that something called [Windows To Go][1] existed a while ago, but it
+was restricted to Enterprise versions. Eventually I found out that creating a
+Windows To Go drive is a really straightforward process:
+
+1. Partition the External Drive and format it as NTFS.
+2. Expand the Windows image using `dism`.
+3. Install BOOTMGR using `bcdboot`.
+4. Boot from the External Drive and continue the setup.
+
+The process was so straightforward that I tried to do everything from the Linux
+side, but I encountered some issues and eventually gave up. It may actually be
+doable, because the issues were small:
+
+1. You need to compile the edge version of `ntfs-3g`, and build `wimlib` (linux
+  alternative to dism) linking it against the edge version of `ntfs-3g` in order
+  to expand Windows 10 images. [Source][2].
+
+2. There isn't a tool like `bcdboot` for Linux, so you need to [install BOOTMGR
+  manually][3].
+
+In the end, I decided to do everything from WinPE and the most straightforward
+way to use WinPE is to boot into the Windows Setup.
+
+## The actual steps
+
+1. Download the ISO from the [official website][4].
+
+2. Boot into the Windows Setup and open the Command Prompt with `Shift + F10`.
+
+    This step is intentionally left ambiguous. There are too many many ways to
+    boot into the Windows Setup. You can [create a bootable USB][5], burn a DVD,
+    you can also mount the ISO and your external disk in VirtualBox.
+
+    This article will use the VirtualBox approach, you can check the
+    instructions to mount your external disk [here][6].
+
+3. Run `diskpart` to partition and format the disk.
+
+    ```
+    list disk                           // list every disk and their number
+    select disk 0                       // change 0 with the # you wish to use
+    clean
+    create partition primary size=512
+    format fs=fat32 quick label=BOOT
+    active
+    assign
+    create partition primary
+    format fs=ntfs quick label=Windows
+    assign
+    list volume                         // you'll need the drive letters later
+    exit
+    ```
+
+    These steps will create an MBR layout in the disk and a boot partition, this
+    is intentional to achieve compatibility with both firmwares: BIOS and UEFI.
+
+    In this example, the `C` drive is the `BOOT` partition, the `D` drive is the
+    Windows Setup DVD, and the `E` drive is the `Windows` partition. The drives
+    in your PC will probably be different, so you'll need to update the
+    instructions for your particular configuration.
+
+4. You'll need the find the `index` of the edition of Windows you wish to
+    install using `dism`. Remember to adjust the `/imagefile:` argument if
+    required:
+
+    ```
+    dism /get-imageinfo /imagefile:D:\sources\install.wim
+    ```
+
+5. Proceed to expand the Windows image with `dism`, in this example I'll be
+    installing `Windows 10 Pro`, which is the 6th index. Remember to adjust the
+    `/imagefile:`, `/index:` and `/applydir:` arguments if required:
+
+    ```
+    dism /apply-image /imagefile:D:\sources\install.wim /index:6 /applydir:E:\
+    ```
+
+6. Install BOOTMGR to the external drive. Remember to adjust the arguments if
+    required; In this example I'm telling `bcdboot` that Windows was expanded to
+    `E:\Windows` and that it should install the bootloader in `C:`; the `/f ALL`
+    argument installs both UEFI and BIOS bootloaders:
+
+    ```
+    bcdboot E:\Windows /s C: /f ALL
+    ```
+
+7. Hide the `BOOT` partition using `diskpart`.
+
+    ```
+    list volume
+    select volume 1                     // select the `BOOT` volume
+    set id=1c                           // `1c` is Hidden FAT32 (LBA)
+    exit
+    ```
+
+8. Finally, turn off the VM, plug the external drive to your PC and continue the
+    Windows Setup. It will proceed to install the drivers and apply the initial
+    configuration.
+
+[1]: https://en.wikipedia.org/wiki/Windows_To_Go
+[2]: https://wimlib.net/forums/viewtopic.php?f=1&t=4
+[3]: http://reboot.pro/topic/20468-create-a-windows-system-from-scratch-using-linux/
+[4]: https://www.microsoft.com/en-us/software-download/windows10ISO
+[5]: https://askubuntu.com/a/487970
+[6]: https://www.serverwatch.com/server-tutorials/using-a-physical-hard-drive-with-a-virtualbox-vm.html