Bootloader questions and sd/usb

@arduinoalador, welcome. The Avrdude, stk500 or Bootloader section is for problems related to uploading your sketch. See About the Avrdude, stk500, Bootloader issues category. Hence your topic has been moved to a more suitable location on the forum.

What kind of data?

What is "the code"? The code of the bootloader?
What is that "bussing that you can do"?