What about the bootloader?

1 and 2 yes.

3 I don't think so, the BL would be expecting a particular protocol, how does it get that from an SD card and there's no mention of it in the BL flow chart which goes like this

start:
is USB enumeration successful?
yes - run SAM-BA
is char # received from UART?
yes - run SAM-BA
goto start

no mention of SD cards.

Looking at the above, how does code execute when you are plugged into the USB, surely it goes into the BL and you would have to manually run the code from there.

cmaglie, do you know?


Rob