Update:
after receiving the rbm tower with the busboard, I confirm that the goldengate works 100% on the top 2 zorro-isa slots. (that is because on this busboard, only the first 4 zorro slots have DMA, like the original 4000 busboard)
so it works like normal, and u can use the remaining 3 zorro-isa slots for the ISA cards :lol: :lol: :lol: