RAM can be disabled or autoconfigured by setting a jumper
notes
the first accelerator board for the A2000
boot ROMs below rev 6 are incompatible with Kickstart 2.0 and above
the ROM address space overlaps the upper 256 kB of the 512 kB Kickstart ROMs (Kickstart 1.3 is 256 kB only)
by the time AmigaOS loads, the boot ROMs are supposed to be off but due to a bug in the A26x0 ROM code they remain active, causing an address space collision
fitting a rev 6 or 7 ROM pair solves the problem
some boards are reported being incompatible with the newer ROMs either