I cant say that I've done this myself, but I was under the impression that merely "shutting the door" isnt enough. You also need to hit run again and it would start where it left off. Again, I cant say for sure, but you didnt mention this so I thought I'd throw it out there. Peter-the-all-knowing will chime in if I'm wrong. Edit: I assume this because this is how the HAAS machines I've used worked. Edit 2: I was just reading the grbl wiki and it appears that I'm wrong. Looks like the default autostart is 4 seconds. I'm not sure if that's changed in custom grbl that OB Control flashes.