You can either RMA the box, or unbrick it using a serial connection (check the sticky in the moding section for a detailed walk through).
Try updating to the latest firmware and see if that fixes your problem.
For Arabic sub the only way to go is to use the txt2vobsub (there are settings to change font size, color and location).
btw, you can also try MedeBO (from my makeover link) it has native support for Arabic external subs.
Best of luck,