I am converting a K40 laser to Smoothieboard. I have steppers and endstops and laser PWM working as of this week. I find that I can press "home" or "home X or "home Y" in Pronterface, and the laser homes. When I press the same buttons in the Web interface, the head moves 10mm to the right (or up for Y) and that's it. The same happens when I issue G28, with or without arguments. G28 works over USB, but only moves 10mm through HTTP.
M119 reports limit switches correctly both on USB and HTTP (I have min & max switches on both axes, but alpha_limit_enable and beta_limit_enable are both false in my config until I figure this out)