Sometime in the past three or four years I decided to develop my own simple hardware OS switcher. With one 27512 Eprom programed and installed you can switch between upto 4 different OSs.
There is no soldering on the motherboard and just a minor amount on the adapter. Attach a 2 position DIP switch or wire for a 4 position rotary switch or use 2 SPST toggle switches. I do not include wiring as there is no real way to know how long or what kind of connector you will need for the other end of the connection.
Finished product may change slightly as different production runs occur. Function remains the same.