bionic 5.886 rooted no 4g

[paulbaril]

I rooted my bionic in jan when i got it to get rid of the bloatware. Never updated and still one orginal rom the phne works fine but will no longer pick up a 4g signal. Been next to the girlfriends xoom and she had 4g and i didnt. I looked into trying to update and changing roms but not sure if that will fix my problem and a little confused on how to do it. Thanks