CSMWrap: Bringing Legacy BIOS to UEFI Systems

CSMWrap is a clever hack that emulates a legacy PC BIOS on UEFI-only systems. Leveraging SeaBIOS's CSM (Compatibility Support Module) and VESA VBIOS, it allows booting FreeDOS, Windows XP, and Windows 7 in QEMU and some real hardware. It achieves this by unlocking the legacy BIOS memory region, loading the SeaBIOS CSM module, configuring memory mapping, and more. Note that Secure Boot and Above 4G Decoding must be disabled, and there may be Windows video modesetting issues.