This isn't a very difficult hack or mod project. You need good soldering skills and the A2630 schematic. If you look at the schematic you will notice the PAL @ U305 has a signal called "68KMODE". This signal is asserted at a logical high state and negated at a logical low state. This signal is normally output from the Auto-Config register @ U303. This register normally comes out of RESET at a logical low state but can be changed to a logical high state by code in the A2630 boot ROMs.
So, if you disconnect the "68KMODE" signal from the Auto_Config register and connect it to a pull-up resistor and toggle switch to GND, you would then have a manual override circuit which bypasses the Auto-Config logic.