Any further ideas on this subject?
You would need the arduino to send the 'start programming' commands to the slave arduino first and then send the finish ones at the end
What I am looking for from the outside seems simple enough. 1) Method to trigger the load of the hex file, or decide to run the already loaded program. This could be a pin held high/low or the existence of a file on the SD card. 2) Program existing in the bootloader which can communicate via SPI to a SD card, and load the hex file into program storage. Reset and we have a new sketch running... Since I don't have a clue to what is really involved, perhaps those much more knowledgeable could chime in and detail what parts of this we are all missing and have kept this from coming to life as of yet.