[spam]
   coda on the jump address stuff:
   it turns out my southbridge reads a data table to initialise the cpu
   before boot. providing this table seems to get the new layout to run at
   boot (although earlier changing the jump address seemed to do it, and
   no longer does. I infer I was cross-eyed again earlier, but a third
   check is needed.)
   I still don't understand all the parts, but the southbridge information
   is enough to make the problem much more manageable.
   --
   regarding the programmer, the headers that arrived are square pin. I
   can use male-female jumper wires though. apparently I also ordered
   backup sockets, so I can in theory troubleshoot the hardware programmer
   issue now, by swapping components.
   to do these tests I was flashing with the internal functionality of the
   board itself which involves a boot cycle every test.