MK312-BT program

Hello,

I succed to make the ET312 work =) (hard and soft)
However, there is a mystery for me, on the screen the arrow up and down are represented by a weard symbol.

Any idea how to fix it ?

I programmed it with an arduino and used the “buttshock-et312-frankenbutt-master” and “f005.bin” file.

Should I use another .bin file ? where can I get it ?
Cheers