Perhaps the "reset r52 interrupt counter" shall does int<='0' instead of int<='1' as I added a not between gatearray and Z80. I have to reproduce the bug into NEXYS4 before all.
I know that ChaseHQ and Arkanoid looks great, so double RAM buffer (from &8000 to &BFFF) is actived, but normaly it shall unlock XOR and P47, so this second RAM part is perhaps badly plugged (A14 inversed ? WR on one and RD on another, double WR on one ?, bad memory size ?)
== Effort done ==