Hi Mate,
Basically I'm an electronics engineer having more than 6 years of experience in Arduino and Raspberry pi based projects. Now I'm working as a IoT full stack developer. I have an expert level knowledge in embedded programming that you are looking for. I'm experienced in both product level as well as research level projects. You can check my profile and old work reviews.
I did the same thing before. So it's so easy for me to change as the way you want. the only thing is that, you need a different bootloader in this work.
Come to chat for more discussions.
Thank you,
Regards
Rohit R Nath