@anyone who knows:
As for some a1ks not having ehb modes, whats the story in regards to dual playfield displays? Are they limited to 3bit + 2bit for playfields? (where does the 6th bitplane come from?)
All chips have 6 bitplanes, you need them for HAM. However they only ever had 32 colours. With an extra bitplane that was only usable for HAM and dual playfield, someone had the idea of making colour 32-63 the same as 0-31 but half the brightness. I'd have added the extra colour registers, but they probably ran out of space.
That's another OCS Denise, it'll work, but not gain you anything. You'll want an 8373R4 for ECS modes. It should just swap in to your A1000.
I thought you needed the ECS blitter as well, which is slightly harder to fit in an a1000.
