hold on a second, a though is my brain entering....
the KS 1.3 chip i have... no wait.. is it 1.2? anyway either or. the point i'm trying to make is, that it came from a rev5 A500, and to get 3.1rom working in a rev5, i had to do a little wiring. lift pin one out the socket, run a wire from hole 1 to leg something, run a second wire to some other chip leg socket combo, do a little dance, put a teapot on your head, and tadaa! it fires up wit 3.1
if the 1.3 chip came from a rev5 A500, would you not have to do the reverse wiring to get it to work in a "standard" rom socket? :-?