Can't call grubx64.efi using startup.nsh in EFI

I installed debian on VirtualBox.
When I launched it I got the regular skip startup.nsh message with the counter and the prompt right after it.

My grubx64.efi resides under FS0:\EFI\debian\, when I tried to call it directly using absolute path it didn't work so I tried putting it in startup.nsh, same result, called it with single and double quotes on both sides, tried escaping the space, still not working.

What can I do in a case where the directory name has space in it?

[Solved], All I had to do is to add the storage device by name and double quotes to handle the space character.

Full procedure:
    edit FS0:\startup.nsh
    FS0:\EFI\debian\grubx64.efi
    < ctrl+s >
    Enter
    < ctrl+q >
    reset
    Watch the magic happens.