The only way I know possible on the '51 does not make sense, but if you have to, here it is: convert from Harvard to VonNeuman using a negative or gate or'ing !WR and !PSEN, this makes all memory the same. Split this 64k between RAM and ROM. Read your serial eprom to RAM, should be a subroutine.
CALL the routine in RAM.
Not what you wanted, but no other way known
Erik