This are two boot-loaders optimized for Atmega and Atxmega micro-controllers.
Both work on the same principle, receive data in Intel hex format for each received line will respond with a status ASCII character.
The Atmega boot-loader is written in ASM language because the Atmega does not have a dedicated bootloader section and eat from application section that is a huge problem for micro-controllers with less than 8KB of FLASH memory.
The Atmega boot-loader project can be cloned/download from here and is made for Atmel Studio.
The Atxmega bootloader is writted in C language and will eat maximum 4050 Bytes of FLASH memory on devices fith more than 128KB of FLASH memory.
The Atxmega boot-loader project can be cloned/download from here and is made for Atmel Studio.
Booth boot-loaders are controlled by an Windows PC x86/AMD64 application write in C# using VS2008.
The PC application project can be cloned/download from here.
All three projects are open source and can be used without limitation.