TL;DR - Dear Ada, do you add in AVR109 to your Atmega32U4 BB's yourselves or not?
I have been using an Atmega32u4 breakout board from Adafruit for firmware development. I can't quite sum up how pleased I am with its simplicity and flexibility. But now I come to a critical junction - I need to know whether the AVR109 bootloader that comes with the breakout board is standard issue from Atmel or whether Adafruit programs in this bootloader prior to shipping their product. The datasheet for the Atmega32U4 indicates a default USB bootloader is preprogrammed by Atmel and each 32U4 is shipped with this bootloader, but what is not clear is whether this bootloader they refer to in the datasheet is indeed the AVR109 bootloader. It comes from somewhere! I'd like to know where and how your bootloader gets onto your breakout board.
edit: I am assuming the AVR109 is indeed the standard issue bootloader, as the BB has no indication of the soldering rework necessary to reprogram the chip with a new bootloader. Just adding that so I don't look that stupid... :p