I have two MAG 324 Boxes with the same issue - Just updated to the latest firmware (2.20.11-324) and still freezing in the Menu. I have to unplug the power cable and start back to get it working.
Also, i'm not sure if it's related when watching a movie, the box randomly exits the movie and returns to the menu. Same issue on both boxes.
I sold a lot of these boxes unfortunately, probably having the same issue.
Is there a solution to this issue?