From what others have said these players have some sort of reset hole, best to try this first, the chance of finding another working firmware for this player is slim as it is an unbranded Onda vx858 copy.
The memory is ok though, it is normal for these Rockchip players to display the amount of memory free, not the memory used.
I would advise against experimenting with different firmwares as you would probably "brick" the player, unless of course as a last resort if the player is unusable and returning to the seller is not an option.
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