Martin tipped us off to an AVR/Arduino serial and mmc/SD card bootlaoder. It was designed to fit the same 2kb memory area that the usual Arduino booloader fits into, but can load firmware from an SD card too. Very useful for on “in the field” programing.
This is a proof-of-concept dual bootloader for Atmel AVR atmega chips. It combines a serial bootloader and a mmc/sd card based one in the same 2kb of flash memory that is normally used by the arduino serial loader alone.
You might ask Why? Well, I have quite a few arduino “in the field”. I can simply drag a .hex file to an SD card, insert it in an SD shield, and field-upgrade my boards without additional hardware. At the same time, I can connect the serial port and start developping with the normal Arduino IDE.