Hi,
I am very much interested in your project as I believe I have the expertise, knowledge, skills and tools to do your project. I am embedded software developer with more than 12 years of experience of professional embedded software development. Please take a look onto my profile to know more about me.
I have quite a lot experience of ARM processors specifically Cortex M0/M3/M4. I have written and used low level, middleware as well as higher level code. I have J-link debuggers, STM32F development boards (STM32F107, STM32F429, STM32F405 and STM32F407). I have quite a lot experience with IAR, ARM GCC and Keil compilers.
I did exaclty a similar project (https://www.freelancer.com/projects/c-programming/Custom-bootloader-for-Atmel-SAMD/details) last year where I developed a bootloader for Adafruit Feather M0 Adalogger in Atmel Studio that loads the application stored in the SD card. The application is encrypted using AES algorithm so the bootloader does decryption and replaces the current one. I also wrote python script that does the encryption of the application stored in the SD card.
I can also help you in configuring SSD1306 display. Give me the details of that part of job.
Let me know if you have any questions.
Regards,
/Ibrahim