I just stumbled upon this post...is this about getting 5200(and 800) carts to auto-launch? I am getting ready to build out an 800 and 5200 section on my build. I started with the 5200 and I spent the better part of this afternoon trying to work through the RetroPie documentation of loading carts, extracting, saving, etc. and I only got three to autoload so far...
Though in fairness, it was a busy day for me building JavaScript rules for online ordering templates for some of our customers, lol....among other things...