Windows 7, UEFI vs BIOS, GPT vs MBR notes

I’ve been digging and experimenting quite a bit with the boot processes in Windows 7 (64-bit only), trying to accomplish completely unsupported things.

Here’s a couple things I have learned that you might find helpful

  • 32-bit Windows cannot boot uefi, nor can it be booted from a (microsoft) efi bootloader. This includes Thin PC.
  • The actual windows partition and installation doesn’t seem to care how it is booted – and it doesn’t matter how it was installed:
    • For UEFI, \Windows\system32\winload.efi is used to boot
    • For BIOS, \Windows\system32\winload.exe is used instead
    • Both sets of files exist regardless the type of system windows is installed on, and can be used interchangeably – I have taken a windows folder installed on a UEFI machine and booted in on a BIOS machine, and vice versa
  • Windows Image Backups are always MBR, even if the source drive was GPT. (at least for the partition containing windows)
  • Windows Image Backup’s recovery tool will not allow you to restore from a UEFI machine to a BIOS machine but…
  • Because the image is MBR, you can boot it on a BIOS machine with a little work

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