Only really old bioses would boot to yboxdash.xbe
One way of finding out which xbe is the right one would be to launch each one and see what it does. You could use an app with a file manager (such as unleashx, xbmc, dvd2xbox) to launch it or you could add lines to your evox.ini. evoxdash.xbe is most likely the xbe that your xbox is booting to.