Since almost every Embedded project needs a bootloader and application for flashing firmware, I've decided to open-source my solution. The idea is to have a universal bootloader for all microcontrollers and a single flasher application. Another idea is to have a flashing application that can run on all operating systems. This is where I open-sourced IMBootloader , IMFlahser together with the IMLedBlink example. Let shortly explain them. IMBootloader Adapter functions For anyone who wants to port this bootloader, it needs to do it through adapter functions. The source file of adapter functions is here: firmware_update_adapter.c Magic key IMBootlaoder is running at interrupt events from USB. In the beginning, it will check if firmware exists by checking the special part of flash and it will looking for the magic key. If the magic key exists bootloader will jump to the firmware. It is to keep booting time short as possible. If the magic key is not written bootloader will listen