Relevant information:

• https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/install-windows-from-a-usb-flash-drive
• https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/split-a-windows-image--wim--file-to-span-across-multiple-dvds#usb-deployment
• https://rys.pw/operating_systems#windows_images

Requirements

• TODO: Investigate whether shoving the raw UDF filesystem into a partition in a new MBR does the trick without any filesystem parsing
  • Investigate how many UEFI firmwares will start crying after seeing it
  • Still need to find a MBR boot sector that can parse enough of it and jump into Crapdows
  • Investigate how many legacy BIOS firmwares will try to parse it even if they're not supposed to and die
• DVD image
  • Mount Windows ISOs (UDF) (possibly without root, maybe without actually mounting them but reading the image directly with some library)
    • Wrapper for GRUB's read-only filesystem driver: https://github.com/coreos/grub/blob/2.02-coreos/grub-core/fs/udf.c
• MBR
  • Be able to create a MBR partition table with one partition
    • Embed fdisk from Termux, or implement it in Kotlin, either way it should be fairly easy
  • Find a suitable MBR boot sector - syslinux should have a few Windows boot sectors, investigate whether they're okay for Windows installer disks
• FAT32
  • Create FAT32 filesystems (shouldn't be too hard - mkdosfs from Termux)
  • Read/write FAT32 filesystems (libaums can do that)
• UEFI
  • Nothing to be done, just ensure the filesystem of choice is supported by 100% firmwares or add a FAT32 ESP
• Too large install.wim
  • wimlib (a Java wrapper needs to be written)

Once the requirements are met, the app will have to:

• Create a MBR partition table on the USB drive
• Add one big FAT32 partition (we might be able to use Android's USB format feature)
• Copy the image content (not the image itself) to the partition
• If install.wim is too big, split it.

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