Symbol fonts in Firefox

Hey everyone,

I’m trying desperately to get my symbol font working in FireFox so I don’t have to create dozens of retina icons and it is easy to change the size and colour.

I’m using it on a Tumblr theme and the files are hosted on Tumblr but I’m guessing Tumblr’s servers have issues with unicode? Not sure on this. I’m using Fontello which says that the files need to be hosted on the same site, which they are.

When viewing the theme in Firefox the icons appear as little squares, although a couple work like the music note for example.

Can’t really supply a link as it will be eventually uploaded here. Any advice or workarounds would be awesome!

@font-face {
    font-family: 'Entypo';
    src: url('fonts/Entypo.eot');
    src: url('fonts/Entypo.eot?#iefix') format('embedded-opentype'),
        url('fonts/Entypo.svg#Entypo') format('svg'),
        url('fonts/Entypo.woff') format('woff'),
        url('fonts/Entypo.ttf') format('truetype');
    font-weight: normal;
    font-style: normal;
    font-smooth: always;
      -webkit-font-smoothing: antialiased;
}

Are the files hosted on your own website? Mines hosted on Tumblr and I have a feeling Tumblr doesn’t allow this. It’s driving me nuts. Tried so many different variations now.