Sorry we are a bit short of helpers at the moment and we are only spare time / part timers
I think it will be worth trying the recovery tool again, Does your player have a reset hole on the side, try sticking a paper clip end in if it has it should reboot.
As an absolute last resort I have had to open my player up and do a hard reset. here is what I did:-
Did anyboby buy this PMP from Tinydeal?
Have a possible firmware ready. if you have no backup there is a firmware for a player looking like yours here:-
Home in the Rockchip section.
No guarantees but these usually can be recovered with persistance, but be careful not to break your player!