My font-awesome fix...

font-awesome.css.less.erb

@font-face {
  font-family: 'FontAwesome';
  src: url('<%= asset_path('fontawesome-webfont.eot') %>');
  src: url('<%= asset_path('fontawesome-webfont.eot') %>?#iefix') format('embedded-opentype'),
     url('<%= asset_path('fontawesome-webfont.woff') %>') format('woff'),
     url('<%= asset_path('fontawesome-webfont.ttf') %>') format('truetype'),
     url('<%= asset_path('fontawesome-webfont.svgz') %>#FontAwesomeRegular') format('svg'),
     url('<%= asset_path('fontawesome-webfont.svg') %>#FontAwesomeRegular') format('svg');
  font-weight: normal;
  font-style: normal;
}