New post: Create Windows 10 Install Drive

Signed-off-by: Ettore Dreucci <ettore.dreucci@gmail.com>

content/blog/win10-install-drive.md

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+---
+title: "Create Windows 10 Install Drive"
+tags: ["win10", "uefi", "bios", "drive"]
+categories: ["recipe"]
+description: "How to create a Windows 10 (UEFI and BIOS) install drive in Linux"
+date: 2020-05-30T10:11:13+02:00
+author: "Ettore Dreucci"
+draft: false
+---
+
+
+
+## [[recipe]({{< ref "/categories/recipe" >}})]: How to create a Windows 10 (UEFI and BIOS) install drive in Linux
+
+Latests Win10 image released by Microsoft have the `install.wim` file way above 4GB and FAT32 formatted devices cannot handle file bigger than 4GB in size. You could use a NTFS partition but that will reduce the number of machines you’ll be able to use the drive on because some (older) systems can’t boot from NTFS drive.
+
+An option is to use a small FAT32 partition that will contains only the NTFS UEFI drivers and bootloader and a bigger NTFS partition that will contains the Win10 image.
+
+Another option is to compress the `install.wim` file with [wimlib](https://wimlib.net/), an open source, cross-platform library for modifying [Windows Imaging](https://en.wikipedia.org/wiki/Windows_Imaging_Format) archives. This is what we’ll be doing:
+
+#### Mount Win10 ISO and extract `install.wim`
+
+We need to mount the ISO and copy the `install.wim` file somewhere else to be able to shrink it because `ISO-9660` is a read-only filesystem
+
+```
+mount -o loop /path/to/win10.iso /iso/mount/point
+mkdir /tmp/win10
+rsync -av --no-owner --no-group --progress /iso/mount/point/sources/install.wim /tmp/win10
+```
+
+#### Compress it
+
+Using the `wimoptimize` utility with the `--solid` option we can achieve remarkable compression rates:
+
+`wimoptimize --solid /tmp/win10/install.wim`
+
+```
+wimoptimize --solid install.wim
+"install.wim" original size: 4266040 KiB
+Using LZMS compression with 4 threads
+Archiving file data: 9434 MiB of 9434 MiB (100%) done
+"install.wim" optimized size: 3170257 KiB
+Space saved: 1095782 KiB
+```
+
+#### Format the drive
+
+Now that the `install.wim` file can be fitted in a FAT32 partition we can prepare the drive.
+
+1. First we need to create a GPT partition table on the drive: 
+
+   `sudo gdisk /dev/sdXYZ`
+
+   which will then ask for some commands:
+
+   - `o` to create a new GPT partition table
+   - `n` to create a new partition
+   - `w` to apply the changes to the drive
+
+2. Then we need to FAT32-format the partition:
+
+   `sudo mkfs.vfat /dev/sdXYZ123`
+
+#### Mount the drive and copy the data
+
+When the drive is ready we can mount it and copy data from the ISO, excluding the old `install.wim`:
+
+```
+sudo mount /dev/sdXYZ123 /drive/mount/point
+rsync -av --progress /iso/mount/point /drive/mount/point --exclude sources/install.wim
+```
+
+Then we’ll copy the new compressed file:
+
+`rsync -av --progress /tmp/win10/install.wim /drive/mount/point`
+
+#### Boot
+
+The drive should now be ready. Go try it and boot!