     $D0B3/53427/SCPU+67:   Enhanced Optimization Register (V2 only!)

       +----------+---------------------------------------------------+
       | Bits 7-0 |   00xxx1BZ = VIC-Bank 0, $0000 - $3FFF            |                                    |
       |          |   01xxx0B0 = VIC-Bank 1, $4000 - $7FFF            |
       |          |   00xxx0B0 = VIC-Bank 2, $8000 - $BFFF (GEOS)     |
       |          |   01xxx1B0 = VIC-Bank 3, $C000 - $FFFF            |
       |          |   10xxx0B0 = BASIC Opt., $0400 - $07FF            |
       |          |   11xxx00Z = No Opt all mem, $0:0000 - $1:FFFF    |
       |          |               V2: Default                         |
       |          |   11xxx1BZ = No Opt per bank, $0000 - $FFFF       |
       |          |   10xxx100 = Full optimization (no mirroring)     |
       +----------+---------------------------------------------------+

         This register is read only with hardware registers disabled,
         Read/Write with hardware registers enabled.

         Changing values in this area affects all other optimization mode
         registers, and changing other optimization mode registers affect
         this location. The B-flag assigns control of this register to a
         specific C128 bank (0 = Bank 0, 1 = Bank 1), while the Z-flag
         controls mirroring of Zero Page and Stack memory ($0000 - $01FF)
         (0 = mirroring on, 1 = mirroring off). Default for Z is 1, B is 0.