Not entirely true - there are two distinct AutoConfig spaces: $200000-$9FFFFF for large allocations (8 MB total) and $E90000-$EFFFFF (7x 64 KB) for small allocations (i.e. I/O). Any additional board failing to allocate memory space will just stay unconfigured/shut up.
So, in theory this should work. A possible problem might be that the two chunks get linked together and something rises from that. Have you tried adjusting the mask value of your partitions so the buffers don't end up in 32 bit RAM? Another approach may be to limit the GVP to 4 MB and AddMem the last 2 MB manually after booting (depending on the board's hardware this may not work).
How would one create a ram board that stops the AddMem command from working?
