hi
Im a noob to both the xbox and linux so this may be the wrong way to do it but it worked for me in xebian
open a terminal and type the following
cd ..
wget
ftp://ftp.mozilla.org/pub/mozilla.org/fir...2.0.0.20.tar.gztar -zxvf firefox-2.0.0.20.tar.gz
close the terminal and open emelfm
change to the home diectory in there you should find a firefox folder open that and start the file firefox
all done