Plasmo: Tying MREQ* to CS* of the RAM and ROM would work but the switching of OE* might require some glue. At power-on the ROM's OE* needs to be low and the RAM's high which can be done via pull-down / pull-up. After the copy, the ROM's OE* can go high from a KIO port. HOWEVER, the RAM's OE* needs to be tied to RD* or possibly NOT WR* after the switch to avoid bus contention during RAM writes i.e. simultaneous RD* and WR* from/to RAM.
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