Since the maintenance crystal hd driver installation doesn’t seem to work anymore, here is how to install the crystal hd drivers using a mac.
1st you ssh into your apple tv by typing this into terminal without the quotation marks “ssh firstname.lastname@example.org” then press enter.
Then copy and paste this without the quotations marks (or just type it in if you prefer) into terminal and hit enter. "
ite com.teamxbmc.xbmclauncher XBMCAdditionalDownloadPlistURLs -array-add http://crystalhd.sartori.at/files/crystalhd.plist "
Then go to your apple tv, go to XBMC, go to the Downloads section, and you will see crystal hd. Install that and as long as you have the right broadcom crystal hd card, it should work with no problem.