Bootloader/flash utility (via serial bus) for the Atmel ATmega328P.
In fact, this is a project to learn how to programmatically interact with embedded hardware (thus reimplementing e.g. a ringbuffer and using custom sleep functions).
Using armigOS requires the AVR-gcc-libraries to compile the sources. After flashing the binaries to the controller (e.g. with avrdude), the USART interface may be used to interact with the system.
When the controller is running the bootloader, it'll wait roughly 5 seconds before it starts its flashed program. If you press p in this timespan, you can paste an Intel hex file to the controller to flash it.
armigOS is released under the GPLv3.