I had a similar problem with my android box and the guide was off by a few hours. I had to reset the box to factory reset, put the area or city in which relates to the time factor. After doing that, I selected the 12 hour format and save it. I don't have a Mag box so I don't know if you can access the settings or what it allows you to change but a factory reset may put things back to where you can make changes.