The datasheet is pretty clear, but I'd just like to confirm that even with MPNMC=1, the byte addresses 0xFE0000 to 0xFFFFFF cannot be accessed with CS5. I have an 8MB NOR flash that I have to use with the DSP, but its 8K sectors are at the top end of the address space. To put it at 0x800000 would mean wasting all the 8K sectors and one 64K sector, rather than 2 64K sectors.