Thats happend to me first time I was programming the Atmel uP,
I was clumsy enough to write

ORG 200h

MOV P1,#0
...

and I was forced to change processor.

Now i have wright a big warning in my source-code that I'l never
going to set P1,4=SS, P1,5=MOSI, P1,6=MISO and P1,7=CLK.

It will rather be an experience to start using an SPI-memory
as soon as I have redraw the PCB.