the rule of thumb is this....
if its not broke, dont fix it.
if the player plays music and video's, then dont bother messing with the firmware.
there is no reason to "upgrade" the firmware, because 95% of the time, the firmware is specific to the manufacture of your player and with the player your showing, there are more than like 100+ factories in china making them and putting their own firmware onto the player. so any firmware you get most likely is not going to work and your going to "brick" your player.
besides, on these cheap players, a firmware upgrades is never really an upgrade, ever.