Download the latest firmware which was released yesterday, unpack it using something like WinRar and copy it to a usb memory stick, insert the stick into one of the reat usb slots and press Fn2, find the file and click OK to select it, click YES to confirm you want to install the new software.
Your box will probably reboot itself, after it does turn the power off at the rear power switch and turn it back on again. (I don't know if this is really necessary, but I like to do this will any box i own).,