Awsome, the D2Ckey hints to the fact that in the past with the PS1 that they were able to add additional wires to existing 4 and 5 wire installs to enable the chips to be smarter at when and when not to inject code into the PS1.
It sounds like this kind of intelligence is what we are now going to possibly need out of our 4-5 wire chips.
"A good example of the dangers with oversimplified chips are the 4-wire PIC12C508-based PS1 modchips that where very popular around 1997. First, Microchip, the manufacturer of PIC chips, made some changes in the manufacturing process, affecting the in-system clock. This was technically not a manufacturing flaw, as the fault was still within the tolerance specified in the datasheet, but the chips stopped working. If the 5th wire, a clock signal from PS1, had not been stripped (the 5-wire modchips still using the PS1 clock did not have any problems) then there would not have been any problems. Shortly after games appeared that detected active modchips - once again, a few extra wires would have enabled the chip to know when (and when not to) send data."