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Hi everyone!!
I have been lost and here i am again looking for answers.
I see the page and fourm has changed or updated.

Anyway right to the point:

The Data "Bus B" 8 bit a way as saying "yes i have an output unit". Do i have to care about thie bus or stick with LOROM/HIROM , etc MEM map?
Which mem map do i have to trust?

The "B" bus is for parts that want to be able to DMA to/from things that are only on the "A" bus, like cart ROM. As far as I know, this is unused by all existing carts with the exception of the prototype CDROM.