no fix for this, this is a limitation of the firmware on the player
this is an old player basd on an old chip an this problem was never fixed and never will be im afraid
there is no firmware update that will bring the fix and if you do feel the urge to update then do not
please read the following on these players, just as a little side note
http://www.mympxplayer.org/image-vp51898.html
sorry but there is and will not be any fix for this, it is down to bad firmware development of which the chinese developers are very good at!!!!