Edgaras , the only solution is to try all the v3.5.35 and v3.5.37 firmwares here
v3.5.35
http://www.mympxplayer.org/actions-3535-dc15.html
v3.5.37
http://www.mympxplayer.org/actions-3537-dc16.html
As there is no way to tell which firmware would work with your player, you'll need to try all those for your screen size until you get a working one.
For your other post regarding creating a new firmware, logically it is not impossible. However, it is no easy task as there are no open source for it. There is a Swan Project going on at S1mp3.org, but seems that there has been no progress for a couple of months.