#include <WinAPI.au3>
DllCall('kernel32.dll', 'dword', 'GetFirmwareEnvironmentVariableW', 'wstr', '', 'wstr', '{00000000-0000-0000-0000-000000000000}', 'wstr', '', 'dword', 0)
Switch _WinAPI_GetLastError()
Case 1 ;$ERROR_INVALID_FUNCTION
ConsoleWrite('Legacy' & @LF)
Case 998 ;$ERROR_NOACCESS
ConsoleWrite('UEFI' & @LF)
Case Else
ConsoleWrite('Error' & @LF)
EndSwitch