C# Pinvoke判断是UEFI模式还是BIOS模式

[DllImport("kernel32.dll", SetLastError = true)]
        public static extern UInt32 GetFirmwareEnvironmentVariableA([MarshalAs(UnmanagedType.LPWStr)] string lpName, [MarshalAs(UnmanagedType.LPWStr)] string lpGuid, IntPtr pBuffer, UInt32 nSize);
public static bool IsUefi()
        {
            //ERROR_INVALID_FUNCTION 1(0x1)
            //ERROR_NOACCESS 998(0x3E6)
             GetFirmwareEnvironmentVariableA("", "{00000000-0000-0000-0000-000000000000}", IntPtr.Zero, 0);
            if (Marshal.GetLastWin32Error() == 0x1)
            {
                return false;
            }
            else
            {
                return true;
            }
        }