Got on the bench some days ago this Twin Hawk PCB (another board coming from Portugal)
Board booted up and game was playable but with bad graphics :
All the GFX data are stored in four 4Mbit MASK ROMs:
I dumped them in my programmer and the ones @3K and 3J resulted empty :
As proof of this I loaded the dumps into MAME and I was abble to reproduce exactly the same issue :
I replaced the two faulty MASK ROMs with 27c400 EPROM devices
This fixed graphics and board completely.