i also use usbloaer gx did you go to the options and put the hook type into axenesomething?
Are you actually getting into the game or is it freezing in the USB Loader? My suggestions are to make sure your hook type is set right, as Carnage said. Also make sure your iso/wbfs didn't corrupt or anything by trying to load it without codes first.
yes it stands on axnextframe and without codes it works perfect here is a link to my files
https://www.dropbox.com/s/spbamy8g7net3kk/brawlex.rar there is by the codes external yoshi max css but i deleted that code